Originally Posted by chaley
The user calibre is running under doesn't have permission to write on the external drive. Either change the security of the calibre folder on the external drive or copy that folder and all its contents to a place you can write.
Worked like a charm. for anyone else who comes onto this problem the simple fix to change security settings is right click on the drive, open properties, go to security, click edit, click add and write everyone, and give "everyone" the appropriate rights in the box below
many thanks, Calibre has a great user community