USB drive forgetting its drive letter after Windows sleep

I've noticed that any USB drive I have plugged in (HDD or SSD) sometimes isn't appearing in the list of drives after waking up from Windows sleep. I almost never do a full shutdown or hibernate, I just choose sleep. On wake-up, I look in explorer or one commander and my drive G is missing. I go into disk management (or whatever they call it now) and I see the disk there, I see it has a healthy NTFS partition so I just need to right-click it and choose "change drive letters or paths" and assign it G and then suddenly it's back and knows the name I'd assigned it and still has all the data perfectly intact. It just forgets its drive letter. This was happening on the HDD I'd been using the last few years (on this laptop and on the previous one too). Last week I upgraded the external drive from HDD to SSD and I've now observed the same thing happens. It's not happening with every sleep, but a couple of times per week.

Are they plugged directly into the laptop or do you use a hub?

Porthos said:

Are they plugged directly into the laptop or do you use a hub?

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I've tried both. The most recent instance (this morning) was when this external USB-SSD was plugged directly into a USB-C(3.2) port. It doesn't get more modern and lovely than that.

It's not a huge deal having to run the disk management tool and re-assign the drive letter to it, but I should add ... once or twice a year the situation is worse than just losing the drive letter - it loses the partition and therefore all the data. Luckily I can restore from a backup.

Another issue here is that quite often my machine wakes from sleep and the external USB drive is totally missing. It's not that it's there but forgot it's drive letter, it's that it's not there at all. I have to unplug it and plug back in. I just tried switching it to the USB port on the machine that is defined as being "the one to use for charging other devices because it's got the most power" - hopefully that ends up helping.

I have a PC and had similar issues with a usb ssd drive. However I never had the problem with a powered USB HDD. I had to connect external power to my usb ssd to keep it from happening.
I do not own a modern standby device so can not test if the setting is even available, but you can try going into power options>advanced power settings and disabling usb selective suspend. Also set hard disk to turn off as 'never'. It may work for you but I suspect this issue is tied to modern standby and its idiosyncrasies. Note that your laptop will use more battery power.

An external power source to your external drive (if it allows it) may help you as well. It unfortunate that in a lot of cases these devices do not even have a connection so that external power can be applied.

glasskuter said:

I have a PC and had similar issues with a usb ssd drive. However I never had the problem with a powered USB HDD. I had to connect external power to my usb ssd to keep it from happening.
I do not own a modern standby device so can not test if the setting is even available, but you can try going into power options>advanced power settings and disabling usb selective suspend. Also set hard disk to turn off as 'never'. It may work for you but I suspect this issue is tied to modern standby and its idiosyncrasies. Note that your laptop will use more battery power.

An external power source to your external drive (if it allows it) may help you as well. It unfortunate that in a lot of cases these devices do not even have a connection so that external power can be applied.

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Interesting. Thanks. I just noticed that I had USB selective suspend setting set to enabled when on battery. I have a home automation timer on my charger so that during the night (when the laptop is in sleep mode) it turns off the power for 2 hours, then turns it on for 1 hour, and repeats. This is on long enough to stop the battery going into low-battery warning and keep the charge topped up. The goal there is to save electricity. I just disabled the USB selective suspend setting on battery. It'll be interesting to see if that helps my situation. If it never happens again I won't know if it was that, or the switching the USB port to use the port that's capable of providing sufficient power to charge other devices. Hopefully at least one of these things gets the job done. It could be up to a week before I can truly say that it's better.
As for providing external power, no such possibility with USB SSD drives.

d4005 said:

no such possibility with USB SSD drives

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Yes you can ...with a powered enclosure that accommodates both 2.5 and 3.5 in. drives.

Not only would my external drive become unrecognized when I resumed from sleep but would not be recognized after a restart. From a cold start I've never had a problem.

I tested with this for days. I used 2 ssds, Crucial and WD, with 2 different enclosures, one powered, one using bus power. I also used a WD external usb HDD using bus power. For some reason, both the WD drives exhibited the strange sleep/wake/restart problems when using bus power but the Crucial did not. Maybe it's a coincidence, maybe not.

I also tested using a powered usb hub. This has seemed to make the biggest improvement, though hasn't completely solved all my problems. All external drives wake from sleep 90% of the time now. Where I still have a problem is after a restart I have to unplug and replug the WD drives for Windows to see them. I though there might be a firmware update from WD but haven't found one.

Your case and mine are somewhat like apples and oranges since power distribution is so different in a laptop plus you have to deal with the modern standy plague whereas I do not.

Something to be aware of.
Modern standby devices can cause a multitude of issues...sleep/wake problems, overheating, battery drain. There have been reports of them catching fire when carried in a bag and even sitting on a desk with the lid closed. In case you don't know already modern standby (s0 sleep) is not sleep in the sense as we have always known it to be. There are MANY threads in this forum regarding modern standby issues. One that might be of interest to you is here (not your problem specifically but modern standby information in general as well as possible options)

glasskuter said:

<all the great info above>

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So it's not as rare a problem as I thought. I'm going to see how I get on after having disabled the USB selective suspend setting on battery (which my laptop is on battery for several hours during the night) and also having switched to the USB port that is stated to be higher powered than the others.

If that doesn't work, I might plug the troublesome drive into my powered USB hub and make sure that when I wake up my laptop I don't turn on the USB hub power for a few seconds. That should give the laptop the definite signal of "here comes a drive being connected again". I really want to keep my electricity-saving strategy of having everything on my desk except the laptop charger plugged into one big multi-socket with a switch. on it After putting the laptop into sleep I turn off that switch, killing the monitors, chargers, and USB hub all at once. When coming back to it, I turn the power on and then wake the laptop. I'll reverse that and wake the laptop first then a few seconds later power on everything else.

So the initial problem of my G drive not being available or forgetting its drive letter on wakeup seems to have gone away. It's been over a week since I disabled the "USB selective suspend setting set to enabled when on battery" on that drive and I plugged it into the port on my laptop that's designated the one to use if you want more charging power and that's done the trick on that particular drive.

However ... my other USB drive (J) spends 99% of its time plugged into a powered USB hub which has switches for each port where you can turn them off fully. Once a week I turn this drive on, do a full backup/sync of my G drive to that J drive as an offline backup. Being unpowered it's therefore untroubled by ransomware. This drive, when I just turned it on failed to appear in Explorer or OneCommander. A quick check in Disk Management showed it sitting there without a drive letter again. I quickly assigned it J and it popped up in Explorer/OC and had all the data it had a week ago and was fine. It really doesn't like being unpowered. I'm sure that one week I'm going to turn it on for my weekly backup and find that not only has it forgotten its drive letter but has also lost all its data, like happened a couple of weeks ago (in its former HDD form, it's now an SSD).

I remember fighting with windows 3.1 on my 3.5 inche installation disks and my 30MB hard disk drive. How times have changed!!

My work is running WIN11 Enterprise. A known issue from windows 7 and above is power management for the USB drives. It is the first thing I turn off on a computer when I get it. They have the nasty habit of going comatose instead of waking up again, and you have to go through the hassle of reconnecting them, unplugging/re-plugging etc.

In device manager, individually UNCHECK each USB entry that has power management, telling it to NOT let the system turn it off. This has worked for me in the past, but I'm new to windows 11. In less than 24 hours I already dislike it immensely. I'm going to pursue this with my IT department also, since they are zealots and have to go with the latest and greatest Microsoft has to offer. THis is my problem, and similar to the above posts but not exactly. This goes to plug n play functionality that Windows 95 started, and Windows 7 (universal PnP) has forced upon us, and we must fight to do ourselves because windoze wants to control everything.

What is my problem you ask?
I am running an impedance spectroscopy / potentiostat for sample analysis. Typically a test will take a few minutes (less than 20 minutes) but sometimes when we do time sensitive or time lapse testing, we can set the instrument to take measurements every few minutes, or every few hours.

This becomes impossible when the USB port disappears and the instrument and software dongle are both USB connected. What this translates to is lost research hours (time is money), lost data, and so many problems I cannot begin to rant here without blowing a gasket. I will see about never letting the computer sleep, and turning off all power management.