Thanks everyone for your responses!
I got a response from sketchUp support which is as follows...
Note: (I tried option 4 just turned off ruby and back on) it saves as usual now.
"*%(#FF4040)[For file save issues it's typically related to the filesystem on the OS.
- Make sure you're saving locally (no external drive, no network)
- Make sure you're saving to a local, non-cloud based file structure as well... no Livedrive, Dropbox and Google Drive...
- Make sure you're using OS compatible filenames, nothing really long, try to remove non alpha-numeric characters from both filenames and folders
- Confirm if Extensions are in place that could affect file saves, turn off Ruby if necessary
A) http://help.sketchup.com/en/article/1700320]* ".... -SketchUp support team