Solve Error "The Directory is not empty" (0x80070091)

Have you ever dragged out your USB stick out of the USB port while the computer was already writing to the drive? This could fit to your arrow message.

You can just try the following steps:

1. Click on the USB drive using the right mouse key (for example in the Explorer) and select "Properties" from the context menu.
2. On the tab "Tools", you can find the box "Error Checking" and the button "Check Now". Click on this button and on "Start" in the opening new window in order to start the checking of the drive and to fix the file system errors if necessary.

After this procedure, you should be able to delete the folder normally.
2015-11-01 at 19:52