Microsoft Sudoku has once again lost my progress on daily challenges. Please advise when this issue will be fixed and my progress will be restored.

I have the same problem

By accident/chance I found a working solution to the 'not saving completed challenges puzzles'. This worked for me at least for two days now.

The trick is to complete one or more puzzles and then walk away leaving sudoku still connected. After some minutess or so the screen overlays the sudoku standby page with a message that there is a re-synchronisation problem and Sudoku will restart. The screen briefly goes black and then returns with the recent puzzles now saved. Not sure how this is working so will try googling using the term' synchronise and sudoku' and see what surfaces.

Whist waiting I also logged into my same Sudoku account on my laptop and mobile phone and had similar synchronisation messages. Need to do more experimenting to be sure of a definitive answer.

I've tried the instructions of RobinsonSilvestre without any success.

Also deleted the app, then downloaded Sudoku again.

When I went to log into my account my user icon was already showing with my historical score.

I played a few games, then closed the game. When I re-opened Sudoku these games are not showed as played.

Is there a corrupted file on my PC ?

I have been in contact with 'Casual games Support' and received several emails suggesting i uninstall Xbox and Sudoku, shut down, wait, restart etc. No joy. Another suggestion was to find Local State and Temp state files, Zip the files and forward them via reply, if the files are too large use OneDrive.

I don't use OneDrive, preferring to store my stuff on my other machine and don't trust Privacy statements and policies.

The zipped files were huge, one was over 600Mb, I explained this and received another mail asking to go back to step one. All in a strange iteration of English which sometimes made it difficult to read.

The strange thing is uninstalling still leaves your setup and stats files on your computer, not their server. Huge data files taking up large spaces on hard bought disc's

I replied that i was fed up being messed about and i would uninstall and not play again,

Until there is news that the problem has been sorted.

This worked for me, thanks a lot.