@ubi-viral I was able so solve this issue by clearing the 128.0 MB of Reserved Space in the save data. After that I loaded the game and all of my save files were there.

@ubi-viral I have responded to all of the questions in the case file. Thank you.

@ubi-viral I do have cloud saves enabled. Over the summer I switched from an Xbox One to an Xbox X and had no interruption in playing AC Valhalla despite starting the game on the older console.

I did not have a power issue while playing last time. Everything seemed normal.

I play online.

In Saved data I see 25.0 MB next to my Gamertag and 128.0 MB under Reserved space

Playing on Xbox Series X. Last week I played a river raid, everything was fine, no issues with saving. Opened the game up this week to check out Discovery Mode and all of my saves are gone. Currently I can only start a new game, there are loadable files available. I have two other games on my console and neither of them have had any issues with save file disappearing. Any help or advice would be greatly appreciated.