I know this has been talked about on the MAC and PC forums for Bridge and has been an issue with CS3 up to CS5. However, it does not seem to be getting any attention from Adobe.
I have gone through the Mac and Win forums from CS3 to CS5 and there are multiple listings of people losing their keywords. I just lost mine again, after rebuilding them about two weeks ago. On another call, 3782474, Paul graciously produced a script to build your existing keywords. You still have to reenter them! Adobe, PLEASE fix this issue. I copied the keyword file and saved it to a backup location. When I lost my file this last time, I restored that file. It stll did not work! I have not upgraded any Adobe products, other Window products or any patches. The only thing I have been doing for the last couple of weeks is editing photos and going from one storage drive to another within Bridge to locate photos. I'm afraid if I lose the one that I just recreated manually that I will no longer use Bridge since this is one of the features that attracts me to it. I'm sure there are other products that will provide keyword search.
Adobe, I hope you are reading this thread and take control. I am running on Windows 7 and Bridge CS5.
Thanks
Bob