August 11, 2016, 12:41:05 pm
Which version of Lumion are you using? (Have a look at the Settings screen in Lumion to see the product name and version number).
Then please provide:
1. Do you have any foreign language text characters in the file name or folder where you are trying to save to? (that is: non-ASCII, non English/Roman alphabet A to Z characters)?
2. A screencapture of the render to MP4 settings (see my example pic 1)
3. A screencapture of the Windows File SaveAs dialogue, to show the file name of the MP4 and folder where you are trying to save the file to (see my example pic 2).
4. If you save the MP4 file to Desktop, are you able to see it once rendered?
Note to test rendering set MP4 to 1 Star 360p, and render only 1 short clip.