I updated to v5.6 recently and it seems less stable. Has anyone else noticed this. I had no issues using 5.4, and in trying to play with some video clips this morning I had several errors. I finally decided to just go back to version 5.4. Did the exact same things with the same files in the older version with out any issues.
Videos play, just making a few changes to tone or white balance, then going back and forth between the slide show and library resulted in the app hanging and or an error message. The only way to fix it was to close LR and then reopen, this did not and does not happen with v5.4. At least you can go backwards version wise and the catalogue still has everything I did in 5.6.
I've found 5.6 unstable compared to 5.4, specifically the adjustment brush does not always apply the adjusted features. I switched back to v5.4 and no problems. I've been traveling and haven't had time to investigate further.
I have decided to stay on 5.4 for now, I have older bodies so I don't have a need to switch. My video cache was set to 3 GB, so I don't think that was an issue. May be Adobe will release one more upgrade.