Can you send us your Skyline document?
In Skyline you can use the menu item:
File > Share > (complete)
to create a .zip file containing your Skyline document and supporting files, including extracted chromatograms.
If that .zip file is less than 50MB then you can attach it to this support request.
Otherwise, you can upload it here:
https://skyline.ms/files.url
Can you also send us your Skyline Settings?
The way that you export your Skyline settings is to first do:
Settings > Save Current
and then give the settings a name (doesn't matter what name).
Then, after you have given the settings a name, you can then use the menu item:
Settings > Share
to save the settings out to a .skys file.
Please attach that .skys file to this support request.
I believe when you bring up that Score to Run regression window, Skyline goes through all of the retention time predictors that it knows about, and tries to find the one that best fits your data. It sounds like one of these calculators is taking forever, and that calculator might either be saved in your Skyline document, or the .skys file.
(I believe we have some plans to make this Regression window much faster in the next version of Skyline).
-- Nick