Windows – CbsPersist, and other massive files created

permissionsvirtualboxwindowswindows 7

I've never seen anything like this.

I had a drive go bad, and ever since I replaced it, it seems that there are all kinds of permissions errors, to the point where I can't download anything or install anything because I don't have permissions. I can only do these things by logging in as Administrator, but I am not sure even that is working correctly as some folders are marked as read only and if I deselect that and apply, it doesn't actually get applied.

I had vmware and virtualbox installed when the drive went bad, maybe this is related?

But more importantly, I logged in today and nearly immediately, I have 3 CbsPersist logs that are all each over 7GB. As well, there are always a bunch of new temporary install folders, what look to be like Windows install folders, but all on my new drive, which is more than a little weird. Inside these folders is what appears to be language packs, with a setup file that only includes this:

[Compat]  
CriticalFileList=MpOAv.dll| 
PlatformUpdate=true 

Which is referencing a windows defender file. There is also a a setupres.dll in the top level, but most every other folder created is a language folder, although they all only contain a setupres.dll.mui. Is this maybe windows 10 always downloading? Basically I get a new install folder every day.

But more importantly I think are these CbsPersist logs. 2 text files over 7gb in size, all created today, something very weird is going on.

Best Answer

The CBS Persist logs are created by the Windows Module Installer service (TrustedInstaller.exe) and here Windows logs the status of its work related to installing Windows updates and configuring features. The normal log goes to a file CBS.log, but to prevent that file from getting too large, Windows splits them into CBS Persist logs and later compresses them into CAB files with makecab.exe.

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If you have no Windows Update failures, where it would help to look at the files, you can stop the Windows Module Installer service, go to C:\Windows\logs\cbs and delete the files. Windows will recreate them the next time you install updates.