The Create Composition function seems to never finish. The icon with the blue circle just keeps spinning and I eventually have to hit Cancel to stop it.

I'm on Win10, and tried it LRT 5.5 and updated to 5.5.3 and it's still the same. I've tried with a folder with 50+ jpegs and also with just 7 jpegs and also the same thing. Once I choose the folder, LRT starts going and I see the progress bar. Once the progress bar completes, the blue circle icon keeps spinning so I can never make changes with teh sliders or save it. If i drag the window, it seems to refresh the window so that the Composition shows up in the preview, but I can't do anything else since LRT seems to never finish and allow me to use the sliders or save the resulting photo.

Any ideas?

Okay, I could track this down. This currently happens if you load an intermediary sequence which has no ICC color profiles embedded. I'll fix this in the next version.
Until then, please reexport the intermediary sequence via LRTExport, this will embed the correct ICC profiles.

Thanks! I'll give it a shot that way.

Fixed in 5.5.5