$WINDOWS.~BT

[RTCutler]

I have a file named C:\$WINDOWS.~BT which is 25 GB.  I've searched on the Web and found that it is a backup of previous Windows system(s) in case one wants to regress.  I don't want to regress, but I would like to recover 25 GB on my C: disk.  I have found a number of Web entries that purport to tell you how to get rid of it, but they don't work for me.  In particular, the System section of Disk Cleanup does not show a "Temporary Windows Installation Files" option.  I have tried various other ways to delete this folder but nothing has worked.  Can anybody help?  

[rtcutleragain]

OK, nobody answered, but by combining advice from several different posts in different places I managed to brute force it down to 800 KB.  Here's how I did it, in case someone else has the same problem.

First, I ran the following in a CMD window brought up with admin priviledge:

takeown /F C:\$Windows.~BT\* /R /A 
icacls C:\$Windows.~BT\*.* /T /grant administrators:F 
rmdir /S /Q C:\$Windows.~BT\

There were a lot of failures, but it got the folder size down from 25 GB to 12 GB.  Encouraged, I restarted in safe mode (PC Settings, Recovery, Advanced, Restart Now,  ... various options ... safe mode), and then did the above again.  Again there were failures, but now it went down to 800 KB, which is entirely acceptable.

So go figure.  I have no idea what the problem was or how the "solution" worked, but it got me pretty much where I want to be.