Windows – Cannot delete maven target folder in windows 8.1

I have used IntelliJ's maven plugin to build my project with mvn clean install.
It fails on clean due to problems deleting certain folders within the target-directory.

I had this error multiple times and I could always solve it by utilizing unlocker or bash rm -rf <dir>, but not this time.

These are the things I tried to delete the folders:

1. windows explorer > right-click > delete:

   seems to do nothing, not even output an error

2. cygwin > bash rm -rf: rm:

   cannot remove 'tiny_mce/plugins/fullscreen': File exists

   rm: cannot remove 'tiny_mce/plugins/iespell': Directory not empty

3. unlocker > delete:

   unlocker option selection

   error message: could not delete

4. eclipse/intellij > delete

   Java IOException: cannot delete…

I hope there are other options since I cannot continue my work on my local machine as long as I have this problem. And I certainly do not want to switch my workspace and setup everything from the beginning under a new path. This can't be the solution!

Update:

5. Moving the folder to another location

   Strangely, it worked. I still cannot delete that folder, but I could continue my work. However, I want it removed…