MSC 3 - Uploading a score is getting stuck

Trying to upload a score, MuseScore 3 start working, showing the "... processing .. etc" message and a whirling image. After half an hour, the message is still there, the image is still whirling, no score is loaded.
If I interrupt the program, the score remains "half-loaded": the TITLE of the score appears in the score list, but if you click on it, no score is opened. It never happened before. Some release-3 bug?

Thank you
Domenico Alfonsi

PS - If you need it, give me an e-mail address so I send you the mscz file that's giving troubles