Can I delete windows.sys file

  Dave Howson 19:52 13 Nov 2016

I have run out of space in my hard drive and after a bit of analyzing, I found that a windows.sys file is taking upto 145 GB in my hard drive. This is found in the C:\ProgramData\Windows directory and is marked as a system file. I was wondering if it was ok to delete this. I am using Windows 10.

  robin_x 21:09 13 Nov 2016

Run Disk Cleanup and Ccleaner, including Tools > System Restore to remove old Restore Points. Search Create a Restore Point to make a fresh one

This will give you a little bit of space


For W10 Home and W10 Pro, I have neither C:\ProgramData\Windows directory nor "windows.sys" and Google doesn't mention it. Possibly it's app or malware related

Rename it to windows.syk, say, and see if you can boot and use Windows normally

If you can't, boot to Advanced Boot Menu > Command Prompt and type

rename windows.syk windows.sys to put it back again.


Scan with Malwarebytes Free as a precaution

When happy it is not needed, delete it.

  robin_x 21:16 13 Nov 2016

**Correction If you can't, boot to Advanced Boot Menu > Command Prompt and type rename windows.syk windows.sys to put it back again.**

(after navigating to ProgramData\Windows, which may or may not be C: in Advanced Boot Menu)

(In Command Prompt, Type C: then dir to check, or D: then dir, etc

Then cd ProgramData then *cd Windows)

  robin_x 21:17 13 Nov 2016

Bloody formatting on this site....

  beeuuem~2 01:50 14 Nov 2016

Could you give the actual file name that is taking up so much space ?

  alanrwood 11:54 14 Nov 2016

The OP says it is called "windows.sys"

  Fruit Bat /\0/\ 12:59 14 Nov 2016

no windows.sys in my win 10 and only using abot 35 Gb for windows and programs.

As per robinx rename it to windows.syk reboot and see if it has any effect.

  lotvic 13:38 14 Nov 2016

Using W10 pro. C:\ProgramData\ is a hidden folder, you have to enable View hidden folders to see it. My ProgramData folder is 547 MB in total size and there is no windows.sys folder/file

  Dave Howson 06:11 19 Nov 2016

I renamed it to windows.syk and restarted the pc, so far there doesn't seem to be any issue. Should I wait for a couple of days before I permanently delete the file?

  robin_x 08:43 19 Nov 2016

Best to wait if you can. Dpn't forget to run malware scan.

  Secret-Squirrel 10:07 19 Nov 2016

Dave, right click that suspicious file, choose "Properties" then click the "Details" tab. Hopefully the info there will tell you exactly what is and the name of the company that supplied it.

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