How to delete "System Volume Information" folder from external drives?

Solution 1:

The solution is take ownership of the directory "System Volume Information":

Assuming the external drive is named G, Start cmd.exe using "Run as administrator" and type:

G:
cd \
takeown /r /f "System Volume Information"

Answer "y" for yes when asked if to replace all permissions.

This will replace the existing owner SYSTEM by yourself, so you can delete the directory.

EDIT

In Windows 7 & Vista you'll need to check that you're the real administrator:
Unhiding the "real" Administrator account

Solution 2:

Boot to the Recovery Console or a Linux Live CD and delete them. Windows makes it very difficult to delete them while it's running. Before you do it though make sure they won't show up again when you restart windows.

Go to Control Panel → System → System Protection → Make sure that it is off on the external drives.