I loaded up subnautica on PC off gamepass and i find it synced my 25 minute xbox save over...

Thanks for contacting us my name is Samy, I am advisor independent and I will be helping you today.

How are you, Tanner?

On this path, you can find the saves saved on your PC. The hard part will be to know what progress is what you used on your PC and if it hasn't been replaced by your Xbox's progress.

C:\Users\YOURNAME\AppData\LocalLow\Unknown Worlds\Subnautica

Unfortunately this solution only works for the few that have bad overall internet connection for the rest of us with fiber internet and new Xboxes I'm sure it's just subnautica being broken as the guy said below zero syncs just fine subnautica does not I wish they would have just left Cloud out of the equation or at least given us the option to play and load saved off my hard drive

I'm trying to play Subnautica over the cloud on my Xbox One because my original Xbox has performance issues and I'm having the cloud save sync issue.

This happened to me too, I was playing on my PC and the save data may not have synced over correctly (idk). Then I loaded the game up on my Xbox and my save data was gone. When I went on my PC my old save was there but then the game crashed and when I loaded it back up it was the new save from my Xbox. I've looked for the save folder that the Steam version of the game apparently has but its not there on the Xbox App version.

(edit after reading other posts) I did buy the DLC and play it on my PC, twice and then this happened to me. Might be an issue with that.

technically correct but a lot of pc gamepass games I have retrieved the saves and converted to steam and gog successfully, the game must be installed and loaded once to sync, then I use game save manager to backup the save that is stored locally which is also synced to the cloud then a third party tool to convert said save.