Windows file or folder in use - cant be deleted or modified

When trying to delete files or folders, clean malware, or just modify something on your Windows system, windows won't let you, because the file is open in another programm:

Folder In Use / File In Use

The action can't be completed because the folder or a file in it is open in another program

Chose the folder or file and try again

How to find the program which is using the file?

1. Download Microsofts sysinternals tool "process explorer":

    From here: https://live.sysinternals.com/

    From here: https://docs.microsoft.com/en-us/sysinternals/downloads/process-explorer

    From here: https://live.sysinternals.com/procexp.exe

    or from here: https://download.sysinternals.com/files/ProcessExplorer.zip

2. Open procexp.exe with admin rights

3. Use the magnifying glass or press CTRL + F

  

4. Search for the file or foldername (only parts of it will do)

5. Doubleclick the found process or use the process id PID to find the process

In order to show the Handles, which are opened by a process, either go to View\Lower Pane View\Handles or press CTRL+D

6. You can no close the process or close the handle, however closing the handle might crash your application or cause system instability, as process explorer will tell you, too.