Windows Defender doesnt finish full scan

When I try full scan with Windows Defender it doesn't finish the full scan and says:



I restart PC and issue is still there, how do I fix this? I got it working by updating definitions but the issue comes back???? How do I fix it?

EDIT: Also, it freezes and doesn't finish after restarting PC...

These are some trial and error steps:


1) Uninstall all non-Microsoft AV software using the applicable uninstall tool:




2) Open administrative Powershell and copy and paste:

Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage



3) Run Tuneup plus > post a share link






4) Run Microsoft defender offline

zbook said:

These are some trial and error steps:


1) Uninstall all non-Microsoft AV software using the applicable uninstall tool:

[KB146] Uninstallers (removal tools) for common Windows antivirus software

support.eset.com

2) Open administrative Powershell and copy and paste:

Get-AppxPackage Microsoft.SecHealthUI -AllUsers | Reset-AppxPackage



3) Run Tuneup plus > post a share link

https://www.tenforums.com/attachments/bsod-crashes-debugging/360139d1645183596-batch-files-use-bsod-debugging-tuneup_plus_log.zip

Batch files for use in BSOD debugging - Windows 10 Help Forums

Information This thread is for use by the BSOD team to store batch files that can be used to collect additional data, fix settings or anything else that is useful in debugging BSOD problems in Windows 10. The way I see it working is the first

www.tenforums.com

Batch files for use in BSOD debugging - Windows 10 Help Forums

Information This thread is for use by the BSOD team to store batch files that can be used to collect additional data, fix settings or anything else that is useful in debugging BSOD problems in Windows 10. The way I see it working is the first

www.tenforums.com

4) Run Microsoft defender offline

Click to expand...

I don't have any other software. Only official Windows 11 Defender. I used repair and reset tool and when ever using reset tool it goes offline and has to be restarted. I did that but it takes forever to restart.

I also had to keep running full scan for it to complete... and then it returns to not being able to finish again...

I had this problem before, need fix once and for all. I have another PC with same specs, etc and everything works fine on the other PC.

FatherTime said:

I had this problem before, need fix once and for all. I have another PC with same specs, etc and everything works fine on the other PC.

Click to expand...

If the problem is not fixed with the above trial and error steps the perform an in place upgrade repair:

zbook said:

If the problem is not fixed with the above trial and error steps the perform an in place upgrade repair:

Repair Install Windows 11 with an In-place Upgrade Tutorial

This tutorial will show you how to do a repair install of Windows 11 by performing an in-place upgrade without losing anything. If you need to repair or create a new recovery partition or having problems with the Windows 11 operating system on your PC, and the usual solutions will not fix it...

www.elevenforum.com

Click to expand...

Is there any other fixes besides this?

FatherTime said:

Is there any other fixes besides this?

Click to expand...

Sure if you want to wipe everything and start over you can clean install. Do you have a particular reason for not wanting to do a repair install?

glasskuter said:

Sure if you want to wipe everything and start over you can clean install. Do you have a particular reason for not wanting to do a repair install?

Click to expand...

Drive space. If I do repair install, how would I remove the ~20GB of space from windows.old file?

FatherTime said:

how would I remove the ~20GB of space from windows.old file

Click to expand...

from disk cleanup(run as admin) or storage settings by choosing previous windows installations.
reference here

@glasskuter @zbook Thanks for your help, works flawlessly now. One problem, the manufacturer for this PC had custom icons and now File explorer icon shows like this in Task Manager:


How do I fix that?

What had happened which each step in post #3?

Did the in place upgrade repair run smoothly?


This tutorial has a bat script which may or not be useful:

zbook said:

What had happened which each step in post #3?

Did the in place upgrade repair run smoothly?


This tutorial has a bat script which may or not be useful:

Rebuild Icon Cache in Windows 11 Tutorial

This tutorial will show you how to rebuild the icon cache to clear and reset it for your account in Windows 10 and Windows 11. The icons that display for files in Windows are saved in an icon cache so they can be displayed quickly instead of having to manually scan and slowly load them each...

www.elevenforum.com

Click to expand...

I did the repair upgrade. Went smooth now., I can do full scan without interruptions. I will try rebuilding icon cache now.

FatherTime said:

When I try full scan with Windows Defender

Click to expand...

FatherTime said:

I can do full scan without interruptions

Click to expand...

It's good that you have fixed the problem but you should normally only bother running Quick scan.
Quick scan versus full scan and custom scan - MSLearn


All the best,
Denis

Try3 said:

It's good that you have fixed the problem but you should normally only bother running Quick scan.
Quick scan versus full scan and custom scan - MSLearn


All the best,
Denis

Click to expand...

I run full scans once in a while.

I typically run Full scans usually once a month prior to doing my System Backup, always done that for as long as i started backing up my Computer systems

bikemanI7 said:

I typically run Full scans usually once a month prior to doing my System Backup, always done that for as long as i started backing up my Computer systems

Click to expand...

All good!

The full scan issue came back after doing in-place upgrade... I'll just do a new install of Windows 11.

Open the PowerShell with admin privileges and execute the below command to reset Defender Security Center and try full scan again.

FreeBooter said:

Open the PowerShell with admin privileges and execute the below command to reset Defender Security Center and try full scan again.

Code:

Get-AppxPackage *SecHealthUI* | Reset-AppxPackage

Click to expand...

Doesn't work, When I typed this in Powershell, opened Windows Security and it had to restart Windows Security and clicked it and multiple errors came up. Had to restart PC for it to work, ran a scan and it froze/not completed still.

EDIT: I just got this system in January, so I’m doing a clean install of Windows 11 right now and hopefully clean it from all the preloaded junk.

Currently did a clean install and full scan works, will check in a week or so if any problems occur.

I'm sharing this piece of advice suspecting it doesn't apply to you as much as your typical user. I've found Defender doesn't always finish a FULL scan either, but this is because the sleep settings put the unit to sleep before it's done. MS should simply override that when running a full scan.

Another one of a 1000 details MS seems to miss... because I swear they never use their own OS.