After trying the 64bit SVN build of Handbrake I have found that I no longer appear to be able to convert video in to XViD. The conversion runs through and produces a file that corresponds to the size I would expect but when viewed just gives an "inavlid file" error in both VLC (64bit or 32bit) and Quicktime and won't play.

Suspecting that it was the 64 bit version of Handbrake I deleted it and then installed the 32 bit version (9.3) but the problem still persists.

Conversion to other media types such as mkv and mp4 appears to be fine.

Given that this was working fine a few months ago under the 32bit version of the software I can only assume that installing the 64bit version has changed a file somewhere that I can't find. Can anyone suggest a way that I might be able to fix this?

Try looking in ~/Library/Application Support or ~/Library/Preferences for anything Handbrake.

Thanks lowededwookie that seems to have done the trick