Return to the title screen when trying to generate a world.

[10:56:14.513] [1] [WARNING] Failed to read E:\Dropbox\Documents\Klei\OxygenNotIncluded\WorldGenSimSave0.dat
System.IO.IOException: Sharing violation on path E:\Dropbox\Documents\Klei\OxygenNotIncluded\WorldGenSimSave0.dat

There is a file permission error. Check if Controlled Folder Access (Ransomware protection) or antivirus software is interfering. Instructions are explained in this troubleshooting guide. If that does not work it might be an issue with Dropbox.

After moving the Documents folder out of Dropbox, launching the game, and letting it create the Klei folder, I was able to successfully proceed to the Duplicant selection screen.
However, the Documents folder needs to be tied to Dropbox.
Is there any way to get the game to reference the Klei folder in a location other than the Documents folder?

I guess Dropbox wants to update/upload the file while the game is also trying to access it, which does not work. The solution might be to stop Dropbox while playing ONI.

You might be able to configure Dropbox to exclude the Documents/Klei/OxygenNotIncluded folder.

I stopped Dropbox syncing only when I started a new game, and the screen went on successfully.
Thank you very much!

Note that Dropbox might interfere with saving, auto-saving, kplayerprefs.yaml, or installing mods. If you don't see any of those issues then it's probably fine.