I’m annoyed also with this issue, and my image viewer doesn't handle files.xcf
However, I have seen that it crashes only after export when I type another filename, and it has the time to suggest something under what I'm typing. If I type quick enough and hit the enter key before it had the time to suggest me the current filename under what I typed, it doesn’t crash.
So, for the moment, I save the file as 1.xcf, and I export in an empty folder to try the smallest file (I need files to be as small as possible) between png and gif, linear and interlaced.
I save in that order: 1.png 2.png 2.gif 1.gif
Then, I rename the smallest file (usually the linear png, but not systematically).
I had this problem with gimp 2.8 under ubuntu, and still have it under debian.

I'm having this problem with GIMP 2.8 under Ubuntu 12.04. It's really annoying in the first place.
MY SIMPLE SOLUTION: just creating a duplicate (Ctrl + D) before doing saving.

is gimp 2.6.8 compatible with winxp ...this version of gimp is crashing on me when i export an image..will let me save xcf but it crashes when i export ...
thanks for any help

The following workaround worked for me: all you have to do is to rename/delete the directory "C:\users\{your_id}\.gimp-2.8\". Doing so, the next time gimp is loaded it will return back to default, solving problems like the "export" crashing.

I found this solution in a gimper thread, but couldn't share the link (according to this website my post looks too spamy for a new user if I add an off-site url).