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.

Sorry it did not work for you. Perhaps I should hav mentioned that this solution only worked after following earlier advice on this question which I repeat here:

Open the File Explorer and paste the following into the address bar to go to a specific location on your computer:

%userprofile%\AppData\Local\Packages\Microsoft.XboxIdentityProvider_8wekyb3d8bbwe\AC\TokenBroker

Delete any accounts and cache folders that you can see at this location.  

This restored my game progress history for the month to the point that I lost my scores. I have also unistalled any thing related to the Xbox app. This does not appear to impact any of the other MS games like Solitaire.

The message that I get after a wait reads something like RESTART REQUIRED as a banner followed by a message that the game has lost sync. There is a large button to press labelled RESTART. I have had the same message come up on my Android phone version of the game so it does not seem device specific. Good luck.

Quite possibly. But which of the thousands on offer?

I would really like to invite a Microsoft Expert to my house, Here, Sit, Fix, PLEASE!!

Hi, i have followed the above instructions but could not find the 'Repair' button, so uninstalled the app , then reinstalled it. Re- ran the app still have the same problem, lost results for the last four days, i have redone the missing games twice so far today, as i have done on several other days this and last month. I am getting to the point of removing the game altogether and never playing again.

The stat seems to get lost when fetching the stat in the morning, because the ninth saw ok out until this morning. Now it looks like I havn't played it. It doesent say i'm offline eihter.

I don't think the statement "Your progress is saved on your account." is correct. Yesterday I finished March 8 and had completed every day from March 1 - 8. This morning when I opened the game,, It showed I had completed Mar 1 - 6 and 7 and 8th as incomplete. So, it saved somewhere that 1 - 6 were complete, but not 7 and 8. I've tried resetting and reinstalling and the problem returns continuously. I'm about to just delete the app, it's so annoying.