I'm afraid you've left out all kinds of important details, like the exact version of PD365 you're using, what kind of transition did you choose (Prefix, Postfix, Cross or Overlap), how many transitions have you favorited, and how many clips are on your timeline. There might be a difference between having 5 clips and 100, for example.

I don't see any issues with any combination of types on v21.5.3125.1 with 25 timeline clips. I tried it with 3 and with 9 favorites and all work as expected.

It's possible your project has become corrupted, and one thing to try is to select all your timeline content (click on any object then use Ctrl+A to select it all) then use File | New Workspace and paste everything to the new timeline. Save this project with a different name then see if the issue has gone away

Quote I'm afraid you've left out all kinds of important details, like the exact version of PD365 you're using, what kind of transition did you choose (Prefix, Postfix, Cross or Overlap), how many transitions have you favorited, and how many clips are on your timeline. There might be a difference between having 5 clips and 100, for example.

I don't see any issues with any combination of types on v21.5.3125.1 with 25 timeline clips. I tried it with 3 and with 9 favorites and all work as expected.

It's possible your project has become corrupted, and one thing to try is to select all your timeline content (click on any object then use Ctrl+A to select it all) then use File | New Workspace and paste everything to the new timeline. Save this project with a different name then see if the issue has gone away

In this project i'm using v21.5.3125.1, about 100 photos and 400 favorited transitions. It used to work even with bigger numbers until a few months ago, and now it doesn't work

Did you try my suggestion about using New Workspace?

If you still have issues you may want to contact CL tech support from their contact page.

Quote Did you try my suggestion about using New Workspace?

If you still have issues you may want to contact CL tech support from their contact page.

Well, it doesn't help
Even if it would, it's a temporary solution. That's a bug that should be fixed

Quote Well, it doesn't help
Even if it would, it's a temporary solution. That's a bug that should be fixed

That suggestion would only work if the original project had become corrupted. As I haven't been able to replicate the issue, it's unclear if it's a program bug or still something about that specific project.

This forum isn't tech support, so the best option for you would be to report it directly to Cyberlink using the link I provided in my earlier post. I think it would help to use File | Pack Project Materials and upload everything to a cloud folder so you can share the full project with them when you submit a request.

You could also post a link to the packed project here so other forum users can test it - but only do so if you're comfortable sharing the content on a public forum.