I use KdenLive in Ubuntu Linux. Finished with editing, pressed on rendering, chose mp4 format, and it doesn't let me chaneg the destination folder. OK, I started rendering there. Rendering runs for an hour, and file doesn't exist... What to do? Thank you!

and it doesn't let me chaneg the destination folder

If you have a problem like this don't waste your time rendering because it will probably go wrong.

OK, I started rendering there.

There where?

Which Kdenlive version?
It's not normal but it could be a permission issue.