I've seen a few modders lose hundreds of hours of work after uninstalling the editor and/or game to solve a problem.

Before you uninstall the editor and/or game, you should backup your mods.

These are the files and folders you need to save:
  • Data\Mods\<your_mod>
  • Data\Projects\<your_mod>
  • Data\Public\<your_mod>
  • Data\Editor\Mods\<your_mod>
  • %USERPROFILE%\Documents\Larian Studios\Divinity Original Sin 2\Local Mods\<your mod>.pak
If you the latest version of your mod has been released, and you've done no further work on it, you will be safe with only these paths:
  • OPTIONAL: Data\Projects\<your_mod>
  • Data\Editor\Mods\<your_mod>
  • %USERPROFILE%\Documents\Larian Studios\Divinity Original Sin 2\Local Mods\<your mod>.pak
The .PAK file contains the Mods and Public data. It does not contain the Projects metadata, which is used to add the mod to the editor startup menu, but you can easily recreate that metadata with a text editor, so let's call the Projects folder optional.

The most important folder is: Data\Editor\Mods\<your_mod>. The editor generates your mod from the data within. If that data is missing, you will not be able to load your mod again, and there is no possibility of recovery.