Tomtom is only updated on the site, not on the navigation system?

I updated the Tomtom Start50 3 weeks ago, everything is ok.

The next time I turned it on, the display said: No maps available… I then connected it to the PC and opened Tomtom MyDrive Connect, but the navigation system only said: connected to the computer.

I tried reinstalling from the downloads. It started, then I got a message saying there was a higher version (2.21.19.159 2948). I clicked on it, the update started on my PC, and then nothing happened. Nothing came through on my navigation system either.

I called in my PC guy (an expert and always successful) because I thought it might be the PC. He successfully initiated the update, but nothing arrived on the navigation system. After a few seconds, the message "No maps available" appeared again. Despite that, I left the PC on all night, and the result is that it now says "…no storage space available for the cache." There is plenty of storage space. Is the navigation system simply broken and beyond repair?