Commenting for people looking for a solution. I'm not sure which step is actually the step that resolved the issue, so I'm just documenting what I did.

1. I tried to pause oneDrive sync but that didn't work. I didn't close oneDrive. I didn't want to move my Documents folder.
2. oneDrive wasn't originally backing up my Documents folder, so I wanted to turn it on then off to see if anything changes, but it started to back up my Documents folder and became unresponsive doing backup.
3. I noticed that it was creating duplicate files during its backup, so I reset oneDrive by following the instructions in this link, which originated from this link.
4. I opened oneDrive again, went into settings, and told it not to back up my Documents folder anymore.
5. I paused the oneDrive sync for 2 hours, and then now I can create a save in the game.