I bought a new mini 2 last week. I have now flown it 3 seperate days, about 12 flights. Yesterday I took 5 videos. The last video, the best would not open on my computer. see the screen shot. I read where if this happens to re insert the sd card into the drone and start it. Today I flew another 5 times. Again the last video would not open. I reinserted the sd card and turned it on and hit record. The video i took after works but the last video i flew still comes up with this message. any thoughts? I used a different sd card too.

Did you stop the recording before turning the drone off?  Thats normally the cause for the corrupt video.

Try PotPlayer or import it into a video editor to see if it can be played.