What is safe to remove from GameData?

[CobraA1]

I'd like to jump into the prerelease for 1.2. I've already backed up my save, now I'm looking at backing up my mods and cleaning out KSP. Question about that, though: What's safe to remove from GameData? Can I remove everything, or must some things stay in place?

[pincushionman]

Leave the Squad folder. That's the stock one; if you delete it you'll have no parts.

I haz done this

…more than once

Edited September 14, 2016 by pincushionman

[Superfluous J]

Other than the Squad folder, you should keep any configs that mods made for you. I don't know them all, but the big ones for me are Blizzy's toolbar (right in gamedata, toolbar-settings.dat) and KerbalEngineer (gamedata\KerbalEngineer\settings folder)

I personally just drag all the non-Squad folders into another directory for safe keeping.