MuseScore Studio 4.4.2 closing after launch.

I have been using 4.3.1. I then installed 4.4.2 (without Muse Hub). The program installed (deleting the 4.3.1 files) and opened. As soon as i tried to do anything, however, the program closed. Reopening it gave the familiar message "the program closed unexpectedly" - but it would not get past the initial start-up screen (showing icons for new, or all the files I had opened recently). Any keystorke or mouse click simply closed the package. I uninstalled & re-installed, did a fresh download, ran "repair", even tried to put it into a different folder so I could revert quickly to 4.3.1. However despite creating a new folder, the next install deleted the 4.3.1 files, but still refused to run properly.

The OS is Windows 10 pro 64bit, CPU AMD Ryzen 5, 32gb installed RAM, Creative Labs Audigy5/RX sound and a Korg Microkey Air MIDI input. I do not, however, have the virtual TPM 2.0 module activated (so that MS can't install Windows 11).

Anyone any suggestions as to what I try next? I am currently using a re-loaded version of 4.3.1 without problems.