taskhostw using a lot of disk and doing something on windows.old folder

Question

I found my windows 10 machine being very slow and using a lot of hard drive.

Task manager, Disk is reporting 100% usage.

I open up Resource monitor, select disk tab. and sort write column. System and taskhostw.exe are using most of disk.

I check taskhostw, and there are a dozen of entries with references to C:\windows.old\... files

I thought this windows folder was supposed to be dormant, but clearly isn't.

Running disk clean up, clean up system files, and select to remove old versions of windows seems to have resolved the problem

Is this an OS problem? or a sign of something else wrong?

Answer 1

Perhaps Windows Defender is busily checking all of Windows.old.

It seems like you have just completed a major Windows upgrade. In this case, I would leave it to do its work. It might be too soon to get rid of the old Windows version and give up on the possibility to rollback to it if you encounter serious problems.

If everything is OK after about a week, you may use Disk Cleanup to reduce Windows.old. This is not really necessary, as Windows will do it automatically 28 days after the upgrade. It is recommended to wait for this to happen, to leave all options open until then.