The data folder.
However, I'm not sure what would be your next step after re-syncing. If you restore from backup, all data will be overwritten.
Which folder i have to delete, i have no data folder or a folder with this name...

The programme has an option at startup like any other wallet to resynch or rebuild etc.?
I can't start the program... when i delete the Obyte folder, the obyte program is also deleted...