I just got hit by this bug, in a project with more tha 30 clips and a lot of hours of work 
I cant change the speed of any clip, tried changing the language settingg but didnt worked. Is a very important project for tomorrow and I cant continue.
Im on Windows 10.
Hi, can you try to change the speed of only one clip? I suggest that for testing you start a new project with a clip or two a see if you can change the speed as you want.
Hm, this bug is settled on my computer. And language setting, well was the language of the operating system.
Other than that: try with fresh project file and one movie for the moment…
It works great with 60 fps movies of waves and water, slowed down to 0,25… good luck best
Fabian
I had the same problem, tried all the above and finally removed and reinstalled the Shotcut, but the problem still persists. I can only set the time multiplier as an integer. Therefore speeding up videos works (for integer multiplier) but not slow-motion.
I’m using Ubuntu 18.04 with a fresh install of shotcut. I tested the issue with one clip long video aswell as with more difficult project.
Slowing down the video works for me .8 speed, then lowered to .5 speed.
Shotcut 18.07.02
Windows 10 Home
i7-7700k
32GB Ram
That never worked. It is not supported. Only clips in the Source player (or from your file manager via drag-n-drop) can be added to the Playlist. You can copy a clip from the Timeline to the Source player by using the Copy function in the Timeline.
Hi! I currently have the same issue where the comma in the speed property stop it from functioning. I can multiply by whole numbers but it fails in fractions. I’m running version 18.10.08
On Ubuntu 18.04, Shotcut 18.10.08, I experienced this problem too.
In Region & Language, changing my format to Australia (maintaining 24h clock) solved the problem.
BUT: Shotcut crashes if I set the speed without the leading 0; I.e., I get a crash on “.50”, but no crash on “0.50”; but “.5” didn’t crash. It’s … eerie.
Hi, I’m struck by this bug as well; Shotcut version 18.12.23; Windows 10 64 bit.
As soon as I change the speed of a clip below 0.5 the program stops.
Is there any update on this bug?
I restarted with a new project and the same video and for now the slow motion works (even at 0.1)…