Hi, so this took me literally 3 hours to figure out, which I finally did after looking in the log under %appdata%/UnityHub/logs/info-log.json that an error was produced when reading the hubinfo.json file within a project that was currently saved on an external SSD that has bitlocked enabled and was not unlocked.
The issue is that Unity Hub would open the first time saying ‘Unity Hub has encountered a critical error, and cannot open’, but then consequential times it will open, but will remain completely blank except for the windows minimise, change to fullscreen window, and exit buttons.
You need to fix this by recognising projects hidden behind locked bitlocker drives and flagging the project up as either “locked by drive” in the list, or showing some kind of informational pop-up that says “Some projects in your project list are currently locked behind bitlocked protection. Please unlock the drive and refresh this list to access the project”, then just exclude showing the project in the list (though showing it with a visual hover-over explanation icon like the lack of correct Unity version installation would be much preferred).
Also, only by shutting down the 3 running Unity Hub applications that are running in the background through the Task Manager would allow me to open Unity Hub and actually see anything after I unlocked the drive, meaning it didn’t fix itself and got in a stuck blank page loop unless shutdown completely and opened again for the first time.