The strange thing is that this worked OK two days go but not now. (2018 Professional SP0.1)
I wanted a quick animation for my client, so I saved it using Preview mode. It is really fast! Saves a 42 second animation (1260 frames) in 10 minutes.
It saves the frames in a temporary sub-folder. Then it creates the MP4.Then it deletes the sub-folder.
But today, it did NOT create the MP4. However it DID delete the sub-folder.
I have attached a video showing the problem. I have my file folder superimposed on the Visualize screen.
The upper right corner of Visualize shows the frame Number being rendered. I just dd 2 seconds (60 frames) to demonstrate the problem.
At 0:43 it says "Encoding Movie" (it is creating the MP4).
At 0:45 it is finished. It just deleted the sub-folder.
But where is the MP4?
Again, two days ago I would be seeing an MP4 in this folder!
My work-around was to un-select the "create movie" option. This kept the sub-folder intact! I then used QuickTime Pro to combine the frames into a MOV file.
Not as convenient but it got the job done.