*Note: I have never run data packs in this world. The world was created with the Fabric mod launcher, but the mods have long since been deleted. I have played this world in vanilla Minecraft several times since then without issue, and therefore believe it might have roots in vanilla Minecraft.*

When I try to log into the world, it loads for a split second and then appears with the error message attached in the screenshot. When I press the "Safe Mode" button, nothing appears to happen at all. When I press "Back to Title Screen," it takes me back to the title screen as expected, but gives no hint on how to fix the issue. I cannot create a backup of this world. When I try to load an older version of the world that I have saved on a USB, it works fine (again, no mods installed.)

Even if the team considers this issue invalid, I would truly appreciate any ideas they have to fix it. This is my favorite creative world that I have worked on for many hours and am very proud of. I really hope I will be able to play it again.

Attached is a screenshot of the error screen. I cannot attach the whole world folder, but if there are any parts of it (or anything else) that would be helpful, let me know.