thanks for your reply Tig, I suspect you are right about it being a Windows 7 problem. I am writing to a server but I don't understand why it is only happening with Sketchup. I will continue to monitor it.

I am looking for some help.

I have noticed a problem with my SU files not saving properly.

I am running SU 8 on a PC with Windows 7.0

This problem happens when I click the close (red X top right)button (not having saved the file). I then get the message do I want to save and I click yes. Then the file does not save but both the file and the back-up file stay at the last saved version. However, and luckily a file is written in the same folder named "0.skb" which I can rename .skp and get my work back. When I try and re-open the original file straight away I am told that it is in use although I know this is not the case.

I suspect that this may be a Windows problem but I am wondering if anyone has heard of this problem? many thanks for your help - David Jamieson