Excel - No permission to save files in ANY location

Hi, 

I've read previous threads on this, and followed all advice given. Simply trying to save an Excel document into a folder (which I do frequently) however all of a sudden it says "You do not have permission to save files in this location" - which I do. Have been through the entire folder and set Read & Write. I have tried to save to multiple different locations with no joy. 

**UPDATE** - I had an 'illegal character' in the title     /    It worked when I removed this

Stuck... and will lose the data I've spent ages putting into my spreadsheet!!