If your user account does not have administrator rights, you will need to log in with an appropriate admin account. The most common reason why you cannot delete a file is lack of user rights on the system.
Method 1: Delete file/folder as administrator With the following 3 methods you can still get rid of such files or folders. In some cases such files remain “marked” as open / “in-use” or you simply do not have the user-rights to delete them.
This might be quite annoying if you definitely don’t need the affected files/folders anymore, like in the case of files that had been used or created by an already uninstalled or removed software.