Duplicate nodes for everything in umbraco admin dashboard

Question

Suddenly we have duplicate nodes of EVERYTHING on our admin dashboard, what gives?

I checked the DB, there are no duplicate published=1 nodes. Using Umbraco 6.1.6

Answer 1

I solved this by Deleting the "cache" folder which is the App_Data folder. The site rebuilds this index. There must have been duplicates in the App_Data folder, clearing this folder solved the issue for me.