Solved Should You Run System File Checker (SFC) Periodically?

There are tons of threads about the built in disk optimiser in Windows going back to the start of Windows 10, the app used to be just disk defragmenter, then they bolted on SSD recognition and the result, in my opinion is a buggy mess.
Some people say that only mechanical drives can have a schedule set, Microsoft tech posters think your drive might have bad sectors causing the optimisation to fail and so on and on.
Is the status of your C drive at 31 days since last try due to it being the boot drive and constantly in use? Or was the machine shutdown during the time it should have run? Or is the scheduling just broken?
You have two options really, first just set a schedule, forget about it and never check the app again or second, manually optimise and turn the schedule off. You can still use the app to analyze your drives to determine if optimisation is needed or not.

DigitalGoat said:

Is the status of your C drive at 31 days since last try due to it being the boot drive and constantly in use? Or was the machine shutdown during the time it should have run? Or is the scheduling just broken?
You have two options really, first just set a schedule, forget about it and never check the app again or second, manually optimise and turn the schedule off. You can still use the app to analyze your drives to determine if optimisation is needed or not.

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Thank you for your comment.

Boot drive being constantly in use? No. I tend to turn my computer on and off one to four times per day. When I am not using it, it gets turned off.

Shutdown when it was supposed to run? Perhaps. If the time that it is supposed to run is at 3 a.m., then it was shut down. I would expect, though, that it check to see if there are any outstanding items and run those items when it is turned on. My expectations and computer reality may be completely divorced, however. If so, that makes the case for setting a schedule?

I am in the schedule camp.

As an aside, I also have Norton 360 (yeah, I know, many dislike Norton) and it will run optimization periodically. I have toggled Norton's switches so that it no longer Optimizes my drives.

Stecyk said:

My question is, Why is one of the scheduled options one month? If drives are trimmed every ten days at most, then what's the purpose of having a monthly option?

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In post #7 of this thread I see that you have "Scheduled Optimization" turned on.

In post #19 it is shownas being off.

Make sure that this is turned on, if you have not already verified this.

If you already addressed this and I missed it in the posts following your, my apologies for the duplication.

hsehestedt said:

In post #7 of this thread I see that you have "Scheduled Optimization" turned on.

In post #19 it is shownas being off.

Make sure that this is turned on, if you have not already verified this.

If you already addressed this and I missed it in the posts following your, my apologies for the duplication.

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Absolutely no apologies needed nor wanted.

Graphics in Post 19 occurred before graphics in Post 7. In Post 19, we see that some drives were never optimized and that there is no schedule. In Post 7, we see that all drives have been optimized and a schedule has been set.

Post 19 was meant to demonstrate that Windows does not rigorously enforce a ten-day period of using TRIM. Windows might have some system to do that, but if it means that your computer must be running at all times, then perhaps it is best not to rely on that system and instead use the schedule.

Stecyk said:

Thank you for your comment, @BruceR.

Your link certainly indicates what you say is true. I have one observation and one question, though.

My new computer is about a month old. When I ventured into this area, I noticed that my C drive had not been TRIMMed for 31 days. If Windows does this automatically, then why has the C drive not been TRIMMed?

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Your computer was not switched on for one month before you got it?

Stecyk said:

My question is, Why is one of the scheduled options one month? If drives are trimmed every ten days at most, then what's the purpose of having a monthly option?

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Weekly is default but Daily and Monthly are alternative user preferences.

Time is set at Control Panel\All Control Panel Items\Security and Maintenance\Automatic Maintenance.

hsehestedt said:

Going back a few posts in this message, I just wanted to provide a little clarification on the topic of running TRIM.

In a perfect world, you would NEVER need to run TRIM manually or on a scheduled basis, because TRIM runs automatically every time a block of data is deleted on the SSD.

However, we don't live in a perfect world. In real life, here is just one example of the kind of thing that can happen:

A large amount of data can get deleted which causes TRIM to take a long time to complete, during which time the system is rebooted or shutdown, resulting in pending TRIM operations not being completed.

So, when an optimization is kicked off manually or via the schedule for doing so, Windows is simply providing "hints" to the SSD, telling it what blocks it sees as being unused. The SSD then looks at all those blocks to see if they have already been TRIMed, and if any blocks have not been TRIMed, it will perform a TRIM operation on them at that time.

As was noted, TRIM is something very different than SFC. TRIM does not care one bit about the validity or integrity of your data. It's sole reason for living is to ensure that unused blocks on the SSD are erased. With a HDD, if you want to write data to previously used blocks, there is absolutely no difference than writing to blocks that were never used before; you simply write your data to that block and you are done. With an SSD, any block that previously had data on it must first be erased before new data can be placed into that block. In fact, it gets even worse: Even if you want to alter only a single byte of data in a block, you first need to read the contents of the block, erase it, then re-write the entire block of data along with the changes. That process can DRAMATICALLY slow down an SSD, hence the need for TRIM to avoid that scenario. With a properly TRIMed drive, any new writes to the SSD will go to blocks that have already been erased, ensuring that maximum performance is achieved.

Hope this helps to clarify what TRIM is actually doing.

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It doesn't ensure that the blocks in question are erased, as all it does is just mark these blocks as invalid. When talking about SSDs, an unused block is a block that has never been written to, whereas an invalid block is a block that was written to so it still contains data, but this data no longer is valid because the filesystem sees the block as free available (empty) space just like the unused blocks─the only difference being garbage left over from the previous write. It is up to the garage collection of the SSD firmware to decide if or when the blocks will be erased, but also keep in mind that blocks pages on an SSD cannot be individually erased, it means that a whole page block consisting of multiple blocks pages must be erased instead if wanting to achieve this. That's part why the actual erasure gets delayed in this manner, the blocks only get marked so the garbage collection kicks in much later. When garbage collection kicks in, it doesn't necessarily have to erase all the blocks that have been marked invalid. It may decide to leave them alone or erase only those specific pages that it needs to erase to not let the overall performance of the SSD start to get worse significantly over time. Another part of this equation is wear leveling. Erasing cells causes wear on the cells so as a result it makes even more sense for an SSD to wait with the erasure until the last moment, which may turn out to be never. I.e., as opposed to ensuring that the blocks are erased, it's actually trying to avoid that from happening more than really should be needed to ensure that the performance stays high. It usualy means that it doesn't ensure that maximum performance is achieved. Just some near-optimum balance that is close enough to maximum performance, but not so close that it causes too much extra wear and tear in exchange for not enough extra gain in performance. Under normal circumstances with normal SSD usage, over provisioning also helps, significantly, to ensure that no invalid blocks have to be erased any sooner than what's needed to allow this whole strategy to work great.

Stecyk said:

Absolutely no apologies needed nor wanted.

Graphics in Post 19 occurred before graphics in Post 7. In Post 19, we see that some drives were never optimized and that there is no schedule. In Post 7, we see that all drives have been optimized and a schedule has been set.

Post 19 was meant to demonstrate that Windows does not rigorously enforce a ten-day period of using TRIM. Windows might have some system to do that, but if it means that your computer must be running at all times, then perhaps it is best not to rely on that system and instead use the schedule.

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Performing too much maintenance too frequently on Windows causes it to suffer from cleaning sickness.

hdmi said:

Performing too much maintenance too frequently on Windows causes it to suffer from cleaning sickness.

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Yeah, fuzz around too much with just about anything (not just Windows) and you first go beyond the point of diminishing returns to doing more harm than good.

BruceR said:

Your computer was not switched on for one month before you got it?


Weekly is default but Daily and Monthly are alternative user preferences.

Time is set at Control Panel\All Control Panel Items\Security and Maintenance\Automatic Maintenance.

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Hello Bruce and thank you for your comment. I must say that I am puzzled by your question. And I am curious as to what caused you to ask that question?

Regardless, please allow me to answer your question.

You quoted me as saying:

My new computer is about a month old. When I ventured into this area, I noticed that my C drive had not been TRIMMed for 31 days. If Windows does this automatically, then why has the C drive not been TRIMMed?

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So I received my computer mid-January, and I provided that screenshot in mid-February, about 31 days later. Hence my comment. But that still does not address your question. One month before I got my computer, it was just parts waiting to be assembled. I called the manufacturer, detailed exactly what I wanted (RAM memory, number and size of SSDs, Windows 10 or 11, desired graphics card and so on). and then within several days, the computer arrived at my doorstep. So, no, it was physically impossible for my computer to be turned on one month before I got it, because it did not physically exist one month before I got it.

Regarding the Automatic Maintenance, this is what my computer shows:



I then selected "Change maintenance settings."



My brand-new computer has its default set to daily. I don't even see an option to change it, though I may not be looking in the correct location. It doesn't matter, though, because I am happy with the daily schedule.

Hello @BruceR,

I turned off Scheduled optimization last week. My prior post showed that I have Automatic Maintenance set to daily. I have not altered that setting.



As we see from the above screenshot taken just a few minutes ago, my SSD drives were not retrimmed on a weekly basis. I will trim these drives tomorrow, Saturday, as that is when I usually do maintenance.

I thought I would share my results with this board. Perhaps others have different experiences, but it seems that I need to have Scheduled optimization turned on or retrim manually.

I hope this information helps others.

Stecyk said:

Hello @BruceR,

I turned off Scheduled optimization last week. My prior post showed that I have Automatic Maintenance set to daily. I have not altered that setting.

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As we see from the above screenshot taken just a few minutes ago, my SSD drives were not retrimmed on a weekly basis. I will trim these drives tomorrow, Saturday, as that is when I usually do maintenance.

I thought I would share my results with this board. Perhaps others have different experiences, but it seems that I need to have Scheduled optimization turned on or retrim manually.

I hope this information helps others.

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TBH, I really don't see how this could help others. What exactly are you hoping to achieve? Scheduled retrim or no, it's still a ticking time bomb, when you never let the SSD(s) be partially defragged. Manually clicking on the Optimize button has the same effect, but Task Scheduler can do that automatically for you, each time when it's about needed. So, unless you have found some kind of explanation that I haven't, I see no point. To the contrary, having to click on something kills your own efficiency versus not having to. Only when there is a problem with the scheduled type of approach, then it does make sense to do it manually. So then the obvious question becomes, what seems to be the problem you're having with it? Until answered, it's just a question, and will simply not help others.

hdmi said:

TBH, I really don't see how this could help others. What exactly are you hoping to achieve? Scheduled retrim or no, it's still a ticking time bomb, when you never let the SSD(s) be partially defragged. Manually clicking on the Optimize button has the same effect, but Task Scheduler can do that automatically for you, each time when it's about needed. So, unless you have found some kind of explanation that I haven't, I see no point. To the contrary, having to click on something kills your own efficiency versus not having to. Only when there is a problem with the scheduled type of approach, then it does make sense to do it manually. So then the obvious question becomes, what seems to be the problem you're having with it? Until answered, it's just a question, and will simply not help others.

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I enjoyed reading your response. It seems like my prior comment stirred a lot of passion.

Let's rewind the tapes to see if we can make more sense out of my prior comment. I am going to use "points" so that I can refer to my prior comments more readily.

Point One

I began this thread asking: "Should You Run System File Checker (SFC) Periodically?" See link here.

Point Two

Along the way, the thread drifted into TRIM or Retrimming, and how often it should be done. Bruce mentioned that Windows automatically trims weekly, implying, I believe, that we do not need set a Scheduled optimization period. See link here.

Regarding the drifting, Mae West once said, "I used to be Snow White, but I drifted."

Point Three

I acknowledged Bruce's comment and acknowledged his source of information. I then went on to say that my brand-new computer is showing that the drives have not been trimmed for 31 days, which implies that perhaps we do need to set a schedule. Or at least I do. See link here.

Point Four

Bruce then asked if my computer was not switched on one month before I got it. And he then discussed Automatic Maintenance. See link here.

Point Five

I replied to his comment that my computer did not exist one month before I got it; it was just a bucket of parts. I had to specify what I wanted.

And regarding the Automatic Maintenance, my computer has always been set to daily. See link here.

Point Six

As a test, I turned off my Schedule optimization for the past week. I was curious if the weekly or daily maintenance would kick in automatically. See Point Two.

As demonstrated, my computer showed 10 days without retrimming, which is longer than either the daily or weekly periods.

So my conclusion is that I need to set the Scheduled optimization period or do it manually. I should not rely on Windows retrimming automatically for me. I also noted that others may have different experiences. In other words, do your own homework to see if you do or do not need or want to set your Scheduled optimization period. See link here.

Point Seven

I'd like to address your ticking stuff. Given that Scheduled optimization provides the option for daily retrimming, do you really think that any frequency longer than daily is worrisome?

As shown in my prior screenshots, I am going back to having Scheduled optimization set to weekly. And I am confident that I have not set anything ticking in my computer. For my prior screenshot, see link here.

Wrapping Up

For my purposes, setting Scheduled optimization to a weekly setting is a good thing. If I don't set any Schedule optimization, then I need to either do it manually or just forget about it.

Others may have different experiences. And they should, of course, do whatever they want.

Stecyk said:

For my purposes, setting Scheduled optimization to a weekly setting is a good thing. If I don't set any Schedule optimization, then I need to either do it manually or just forget about it.

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Three cookies for a very "neat and legible" response.

Ghot said:

Three cookies for a very "neat and legible" response.

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And I gave him three more!

TraderGary said:

And I gave him three more!

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They were well earned.

Stecyk said:

I enjoyed reading your response. It seems like my prior comment stirred a lot of passion.

Let's rewind the tapes to see if we can make more sense out of my prior comment. I am going to use "points" so that I can refer to my prior comments more readily.

Point One

I began this thread asking: "Should You Run System File Checker (SFC) Periodically?" See link here.

Point Two

Along the way, the thread drifted into TRIM or Retrimming, and how often it should be done. Bruce mentioned that Windows automatically trims weekly, implying, I believe, that we do not need set a Scheduled optimization period. See link here.

Regarding the drifting, Mae West once said, "I used to be Snow White, but I drifted."

Point Three

I acknowledged Bruce's comment and acknowledged his source of information. I then went on to say that my brand-new computer is showing that the drives have not been trimmed for 31 days, which implies that perhaps we do need to set a schedule. Or at least I do. See link here.

Point Four

Bruce then asked if my computer was not switched on one month before I got it. And he then discussed Automatic Maintenance. See link here.

Point Five

I replied to his comment that my computer did not exist one month before I got it; it was just a bucket of parts. I had to specify what I wanted.

And regarding the Automatic Maintenance, my computer has always been set to daily. See link here.

Point Six

As a test, I turned off my Schedule optimization for the past week. I was curious if the weekly or daily maintenance would kick in automatically. See Point Two.

As demonstrated, my computer showed 10 days without retrimming, which is longer than either the daily or weekly periods.

So my conclusion is that I need to set the Scheduled optimization period or do it manually. I should not rely on Windows retrimming automatically for me. I also noted that others may have different experiences. In other words, do your own homework to see if you do or do not need or want to set your Scheduled optimization period. See link here.

Point Seven

I'd like to address your ticking stuff. Given that Scheduled optimization provides the option for daily retrimming, do you really think that any frequency longer than daily is worrisome?

As shown in my prior screenshots, I am going back to having Scheduled optimization set to weekly. And I am confident that I have not set anything ticking in my computer. For my prior screenshot, see link here.

Wrapping Up

For my purposes, setting Scheduled optimization to a weekly setting is a good thing. If I don't set any Schedule optimization, then I need to either do it manually or just forget about it.

Others may have different experiences. And they should, of course, do whatever they want.

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So, to summarize, scheduled retrim works exactly as intended, and, as a result of this unexpected miracle, others might or might not want to doublecheck on that. On a side note, the answer to your question in Point Seven is in my post that you quoted, which clearly states that disabling the scheduled optimization task only becomes a ticking time bomb when you never let the SSD(s) be partially defragged. I can see now how this information will help others. It was a very clever joke, and I almost fell for it. Congratulations! Enjoy your well-deserved cookies. Just remember to not eat too much. Or no, just do whatever you want, kind of like...

hdmi said:

So, to summarize, scheduled retrim works exactly as intended, and, as a result of this unexpected miracle, others might or might not want to doublecheck on that. On a side note, the answer to your question in Point Seven is in my post that you quoted, which clearly states that disabling the scheduled optimization task only becomes a ticking time bomb when you never let the SSD(s) be partially defragged. I can see now how this information will help others. It was a very clever joke, and I almost fell for it. Congratulations! Enjoy your well-deserved cookies. Just remember to not eat too much. Or no, just do whatever you want, kind of like...

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No, your summary is incorrect. No one ever doubted Schedule optimization worked as planned. So there is no miracle. The question was as follows: Do users need to use Schedule optimization because Windows purportedly retrims (not defrags) automatically? As I have demonstrated, I need to either use Schedule optimization or manually engage Trim. Or in other words, I cannot rely on Windows to automatically retrim my SSDs. That said, I believe Bruce acted in good faith in providing his information. While my computer does not act in the manner Bruce suggested, perhaps your or other users' machine do. Others should not necessarily rely on my experience, because I am just one person and may not be representative of a larger population of users. Perhaps I have some setting somewhere that has changed the expected behavior.

Regarding your ticking stuff, no one in this thread—anywhere—suggested retrimming more frequently than daily. And daily is the most frequent option Schedule optimization provides. Because that Windows provides that option, it is probably a good assumption that it is safe. Furthermore, Retrimming is not defragmenting. If you were to defragment your SSDs, you would decrease their lives because of needless writing as it makes files contiguous. As we know, writing to your SSD shortens its life. In fact, when you shop for SSDs, you might come across the term TBW or terabytes written. The higher number, the more terabytes that can be written to the drive before failure.

Below is a screenshot from Samsung Magician, where you see that I have written about 1.8 TB to one of SSDs. It is a relatively new computer, so the number of terabytes written so far is low.

Stecyk said:

No, your summary is incorrect. No one ever doubted Schedule optimization worked as planned. So there is no miracle. The question was as follows: Do users need to use Schedule optimization because Windows purportedly retrims (not defrags) automatically? As I have demonstrated, I need to either use Schedule optimization or manually engage Trim. Or in other words, I cannot rely on Windows to automatically retrim my SSDs. That said, I believe Bruce acted in good faith in providing his information. While my computer does not act in the manner Bruce suggested, perhaps your or other users' machine do. Others should not necessarily rely on my experience, because I am just one person and may not be representative of a larger population of users. Perhaps I have some setting somewhere that has changed the expected behavior.

Regarding your ticking stuff, no one in this thread—anywhere—suggested retrimming more frequently than daily. And daily is the most frequent option Schedule optimization provides. Because that Windows provides that option, it is probably a good assumption that it is safe. Furthermore, Retrimming is not defragmenting. If you were to defragment your SSDs, you would decrease their lives because of needless writing as it makes files contiguous. As we know, writing to your SSD shortens its life. In fact, when you shop for SSDs, you might come across the term TBW or terabytes written. The higher number, the more terabytes that can be written to the drive before failure.

Below is a screenshot from Samsung Magician, where you see that I have written about 1.8 TB to one of SSDs. It is a relatively new computer, so the number of terabytes written so far is low.

View attachment 55089

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I would trim manually weekly if Windows doesn't do it automatically. As for defragging the SSD Windows will partially defrag it if needed.

"
2 – Does Windows 10 / 11 Defrag SSD’s Automatically?
Mostly no. Windows 10 and Windows 11 still have a defragment utility built in but it is now smart enough to flag SSD’s and disable defrag.

However, once a month Windows automatically considers partially defragmenting an SSD if there is exceptional fragmentation that is approaching the ‘maximum fragmentation threshold’. After that threshold is reached the “meta data” for the file fragments exceeds what the SSD can handle causing the SSD to stop reading and writing. This is a bad thing so Microsoft will carefully defrag the rare potentially problematic files."

From:

Running scannow frequently enlarges the CBS text log file so that it can be large when troubleshooting.

Other than that it is useful to run scannow, restorehealth, and chkdsk regularly as they check the status of each:
operating system
component store
drive file system

Stecyk said:

As I have demonstrated, I need to either use Schedule optimization or manually engage Trim. Or in other words, I cannot rely on Windows to automatically retrim my SSDs. That said, I believe Bruce acted in good faith in providing his information. While my computer does not act in the manner Bruce suggested, perhaps your or other users' machine do.

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I did not say that Windows would retrim if scheduled optimization is disabled. The default is enabled.