I have noticed slow grinding to a halt and general all-round buggyness of Bridge for some time.
I am uncertain if this is ONE of the reasons, BUT this happens a lot to me (and just happened on the recent beta as well)..
Bridge starts to index files for a Collection. Then it just stops at a specific folder and don't progress. I have to manually go into that folder and voila, no previews shows up. I then have to delete the cache for THAT folder only, the images reapper and indexing then progresses.
There are no bad jpgs or any specific file that should do this to Bridge. It happens quite often, not always to the same folder either.
Another thing that I find annoying is how little information is provided about what Bridge is doing in the background. It would help knowing it is doing the dishes or vacuming the livingroom while I am trying to find my wallet. I know it says so on a small line, but it is not visually a good way to show it IMHO.
Crash or freeze
Problem or error