However, the good news is 2K does have a method that should prevent the issue, and some players have stated you can contact 2K to recover your NBA 2K21 progress.
NBA 2K21 UserData or MyTEAM Corrupted?
The issue seems in NBA 2K21 seems to be affecting different modes for certain players with PC being the main platform affected, but others could also be impacted.
One Reddit user reported their MyTEAM file was corrupted, but others are posting today stating their MyCAREER save files have been corrupted.
The above screen, posted by Reddit user omssimies, was the first of multiple warnings that data in their NBA 2K21 save file had been corrupted.
However, the good news is that two potential fixes are known, and 2K appears to be working with players who lose their progress.
How to fix UserData or MyTEAM corrupted in NBA 2K21
On the official 2K Support website, there is a new post as of this morning describing the following method of fixing this issue.
2K has explained the issue is with reserved space, and players need to load the game and only select the "Play Now" option rather than heading into the main game.
From there, players are advised to just stay on that menu and leave your platform alone while it downloads data.
"After a few hours (or longer, depending on your internet connection), you will receive a notification in yellow font on the bottom left of your screen telling you to return to the main menu," 2K Support stated. "Once you do, your game will be fully updated and your reserved data will be reinstalled."
If this reported fix doesn't work for you, or you've lost your save file already, the best thing to do is get in touch with 2K Support directly.
One Reddit user stated that 2K was able to restore their save file and badges, but animations and career progress were lost.
Right now, the safest course of action for players is to follow 2K Support's guidelines to fix the issue and to contact 2K Support directly if that doesn't work or if save data has already been lost.