Windows 10: Fixing System Restore Error 0x80070091
Janet Denzel
[German]It seems that a couple of Windows 10 users are facing system restore error 0x80070091. I've blogged about that issue within my German blog, and it seems that my solution works. Here are a few hints for my English readers how to analyze and solve this issue.
I found several forum posts from December 2016 and January 2017 mentions this error code (see here, here, here, here, here for Windows 10, and here for Windows 8). But I came across this error the first time within a German Microsoft Answers forum post. A user describes the the error message as follows:
contains some redirections (subfolders VFS with NTFS links) and could not be deleted. Virtual File System is used by App-V to redirect folders for instance. Perhaps something went wrong during updating apps. Robert Aldwinckle has suggested at Microsoft Answers forum a solution to list the folder's content without changing the permissions or tampering with TrustedInstaller rights. Here are the steps to proceed.
Then launch notepad using the PowerShell command notepad and insert the clipboard content pressing Strg+V. Afterward you can inspect all sub-folders within Windows editor. Search for VFS sub-folders for instance. My suspicion is, that some re-direction could be the cause for the system restore issue.
If a third party antivirus software causes this issue, the most simple approach is, to uninstall this AV software and use a vendor's clean tool to remove also files and settings remaining from uninstalling.
Reboot Windows and check the system for damaged system components, using the advices given within my blog post Check and repair Windows system files and component store. Also try to do a disk check for Windows drive (right click Windows drive, select Properties and use the Tools tab to start a disk scan).
If third party tools blocks system restore, maybe it helps to execute system restore from Windows PE. Just click the On/off button in start menu and select the Restart command while the Shift key has been pressed.
It's possible, to use the approach discussed within this SuperUser thread, and remove all apps via PowerShell. But that probably didn't help, if the app causing the system restore error has been partly removed. Maybe disk cleaning (via Windows drive's property page) helps, but I'm skeptical.
If you have proceeded the steps given above, and your are not successful at all, you run out of "simple click solutions". Then it's time for a more radical approach. We are going now to clean up the folder %ProgramFiles%\WindowsApps that is causing trouble.
The biggest problem is to access the folder %ProgramFiles%\WindowsApps, because this folder is owned by TrustedInstaller and is protected in a special manner. So you are not even able to open this folder within Windows Explorer.
This blog post How to clean up the app folder in Windows 8.1 and 10 (delete apps)! discusses how to use file manager Q-DIR to access the folder %ProgramFiles%\WindowsApps. I've used another approach: I executed the third party file manager Explorer++ portable within the Trusted Installer's context. Trusted Intaller has full access rights to %ProgramFiles%\WindowsApps.
The steps, how to launch Explorer++ portable with Trusted Installer credentials has been discussed within my blog post Windows 10: Execute programs as System/ Trusted Installer. Using this approach, enables me to create a copy of WindowsApps, inspect sub folders and subsequently delete entries.
Some users of my German blog post confirmed, that this solution worked. One user mentioned, that some VFS subfolders contains NTFS links (for folder redirections) and couln't be deleted, but the WindowsApps folder was renameable. System restore set the machine to a previous state, and all apps are also back. If that didn't cure the isse, your are able, to re-rename WindowsApps.old back to WindowsApps and try other fixes.
In case, you are not able to use process hacker and my solution above, or in case some files are locked, try to boot into Windows PE (see Fix #2) and go to the command prompt windows. Then try to enter the following commands (press enter key to execute each command):
The rd command deletes the WindowsApps folder with all sub folders. It's confirmed within this forum post, that the command sequence has worked. Then close command prompt windows and try system restore again. It should work now (if not, try a reboot first).
If fix #5 fails also, it's time to reset your Windows 10 to factory settings, using the Settings app. Hope, the hints given above helps to cure Windows 10 system restore error 0x80070091. Comments and further suggestions are welcome. If it worked for you, please let us know.
Thanks for this great post. #5 fails as explorer++ says windowsapps is being used by other processes. Searching for file handles in processhacker, it's explorer.exe and skypehost.exe. Both can't be 'killed'. They both restart right away.
I looked the file handles opened by explorer. It was xbox something. I used GeekUninstaller mentioned in option #4 to uninstall xbox apps and also skype app from windows store(which is in windowsapps). Then I could rename. Perhaps the rename is not even required as long as there is nothing using handles from windowsapps dir?
Pour moi aussi la solution numro 5 a fonctionn chez moi, une fois la restauration du systme effectue, je n'ai plus eu de message d'erreur l'ouverture d'un fichier EXE.
Merci beaucoup, a m'a vit de devoir tout rinstaller.
The C: drive in system restore PE is a system reserved drive.
Your C: drive should be D: in the system restore.
Try navigate to D: and see list using command Dir. U will see your C: files in there.
If you use the advise given in my linked blog post -10-execute-programs-as-systemtrustedinstaller/ using process hacker to launch explorer++, it runs with truested installer privileges. Then you can use the context menu command Rename to change the folder name.
Renaming the folder %ProgramFiles%\WindowsApps did the trick!
I used Hirens Boot CD to change the name of this folder, then restarted the PC and now System Restore works fine again. Thank you very much
I have tried the #5 option, but am running into an issue. I downloaded Process Hacker, plugins, etc. When I try to click "Run as Trusted Installer.." in Process Hacker it says "This option requires elevation." Did I do something wrong?
Disregard the above comment. I forgot to Run as Administrator. However, I am getting an error after running Explorer++ in Trusted Installer. When I try to change the name of WindowsApps, it says "The action can't be completed because the folder or a file in it is in use in another program". I don't know how that is possible.
Due to the issue I was trying to fix via system restore, I cannot access windows explorer and so am limited to fix #5. However, when I try to enter the second command (takeown /f WindowsApps /r /d y) the system tells me "ERROR: The system cannot find the file specified"
How do I make the folder visible within command prompt? Please explain like I know nothing.
Thanks
I'm having a problem with step #5. In the cmd I'm "Administrator: X:\windows\system32" and after step 1 (I had to use D: instead of C: because it couldn't find C:) I'm "X:\Program Files" running command 2 brings up: ERROR: the system cannot find the file specified.
Using Dir command tells me I have 0 files and 3 dirs. The dirs were forward, backward, (represented as . And .. respectively.) and Common files. Exploring common didn't help. Can anyone help?
I solved the System Restore problem with solution #5 using Windows PE. However :
(A) In the first command (CD) I used D: rather than C:, even though it's C: in normal Windows.
(B) The ICACLS command gave an error message that finished with "no files processed". But this did not prevent the final RENAME command from working.
Ive 3 restorepoints; from 2 of them I can restore but then on both of them I get the recovery loop again.
On one (the last one before KB install) I get a restore error:
error in unpacking C:\windows\stsem32\AppVPublishing.dll
Hi
The hack of #5 worked perfectly for me. I used ubuntu bootable USB. In try mode ubuntu has perfec acces to al Windows folders. Renaming WindowsAps was not an issue. After that restore came with another error but system rebooted and restore was finished successfully. I think the hack with ubuntu is much better. It worked for me when recovering other crashes.
1): My files were in drive D instead of C
2): Had to modify the icacls command line because it failed at first, but after running "icacls /?" I learned that the %USERDOMAIN% portion wasn't ever asked for by icacls so I got rid of it and it ran without errors
3): I renamed WindowsApps to something that better matched my frustration by this point in the process. Let's just say I'm glad this is fixed lol
Besides this issue, I've run into another issue with Win 10 that seems to relate to redirecting folders. After I partitioned the harddrive on my new laptop, I tried to make Windows store My Documents, My Music, My Videos and My Pictures on the newly created "data" E:\ drive. Now the OS is messed up. I'd be happy to give details about what I see.
Basically, I need a Windows expert to fix it for me since I'm not competent to that extent. Could you tell me where I might find a reputable expert on the Internet? I could give them remote access and, naturally, pay a fee.
Moving user profile folders isn't always a good idea! Microsoft doesn't support that in several scenarios (i.e. during feature upgrades), although they provided a path tab in folder settings to move user folders.
Thank you, GL. The user folders did get moved to E:\ but the OS itself is messed up. E.g., User Accounts on C:\ does not see me by name even though I log into my local account by name. Also, the Download folder on C:\ contains not only the few program downloads I have added (like Bitdefender and Paragon Partition Manager) but also most of the Windows files.
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