Windows 10 No HD Space Left for No Reason

Question

I'm running latest version of Windows 10 on my Surface Pro 4 with i7/16GB/512GB.

Of the 475 GB available space on my SSD, I was using roughly 150GB. All of a sudden, for no reason, I'm now down to a few kilobytes of space. Looks like most of the space is used by the Windows folder where the OS is - see below.

I have the built in virus protection on and it's up-to-date and showing no issues. Any ideavwhat would cause this explosion on HD utilization? Especially stuff going into Windows folder?

UPDATE: This is where my space is going and it keeps growing faster than I can make space for it. What should I do?

Answer 1

Your update appears to have provided the answer. CBS.log is a log file for Component Based Servicing, and there seems to be a bug with it that causes it to fill up all available space.

Unlike NBC.log and FOX.log¹, you can delete it safely. You may need to take ownership and delete it that way though.

You need to be logged in as an administrator and run Command Prompt as administrator.

Change to the log file folder (cd C:\Windows\Logs\CBS), take ownership of the file (takeown CBS.log), and then delete it (del CBS.log). You can then exit the command prompt. You should then get most of your space back.

^{1: No such file exists.}

Answer 2

In my case, the Windows\Temp folder grew until almost full the Hard disk space, by unknown reason. Using WinDirStat application running like administrator (running like normal user a lot of used space remains hidden) I discovered 200 GB of files in the Temp folder. I opened a Command prompt like Administrator and executed inside the C:\Windows\Temp the risky operation

del *.*

That recovered a lot of space and Windows doesn't seems to be affected.