If you open permissions on a file or folder and get this message:

Permissions Are Incorrectly Ordered

And if you list files in Cygwin and the user:group looks like this:

[waste@server /cygdrive/e/folder_with_bad_permissions]# ll
total 172K
drwxr-x---+ 1 Unknown+User Unknown+Group 0 Jun 17 2013 folder_a/
drwx------+ 1 Unknown+User Unknown+Group 0 Aug 12 2014 folder_b/
drwxr-x---+ 1 Unknown+User Unknown+Group 0 Mar 4 2010 folder_c/
drwxr-x---+ 1 Unknown+User Unknown+Group 0 Nov 12 2010 folder_d/

You can open a cmd window with administrative privileges and then run the following command:

takeown /r /f e:folder_with_bad_permissions

/r - recursive
/f - file

Manual page for the takeown.exe command.

Note Cygwin was notorious for creating folders with this issue so it may have happened if you inherited a drive with folders created by Cygwin which doesn’t have a correct mapping to users on this drive.

After getting ownership you should be able to open Windows Explorer, right-click on the folder, open the Security Tab and change permissions at will.

Edit: I've received a few emails regarding this issue, and this post on superuser confirms that is a common occurrence. The steps the above apply only when the file is not currently held by a program! If the file is in use, Windows will prevent you from deleting it.

You can use Microsoft Sysinternals - Process Explorer to find out which program is using the file you're trying to delete.

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