Could you please try to import a few fresh videos in Lightroom with the same format and check if you are able to play and work on them.
What is the format of those video files?
What was the origin of those videos?
Is it happening with a particular video file?
If possible, share a screenshot of the exact error message.
I am in a similar situation. LR won't even let me import a video file. Photos yes but it crashes when trying to import MOV files from from my Canon 5D2.
would suggest you to try the following steps :
1. Go to Lightroom Preferences> file handling tab
2. Click on purge cache at the bottom under Video Cache Settings.
3. Relaunch Lightroom and try to import again.
Hi folks I sorted out the problem by restarting light room under Alt Ctrl Shift (as recommended by both of the Adobe people chetna and ?) sorry I cant see her name, and reseting all preferences to default. this gave me back the options to play the video, and to solve the export problem ....in the export window under the video tab, I set the file type to " Original unedited file" and that sorted out the last of my problems. I must say it is nice of adobe to provide software so inherently unstable that so many users have similar problems.in answer to the above by Chetna, next time lightroom, stops I will try your fix but for now it is sorted, if i do get more problems then maybe I will check out another software provider and see if they have a program that works all the time every time.