From EssenceRO Wiki
Failed to get Patch/list.txt on eRO Patcher
Make sure you aren't running a Firewall or Programs like Norton / BitDefender. (These are known to block the Patcher). Also try closing and reopening the Patcher and try again.
Patch Allow Error
- Open up patch_allow.txt in your RO folder.
- Change deny to allow
- Save the changes
- Right-click patch_allow.txt, and go to Properties. Then set it to Read Only.
Failed to move file to original path
"Failed to move file (essdata.grf) to original path, temporary name is neoncube\neoncube.grf"
This happens if the EssenceRO client is open while patching. Close all instances of the EssenceRO client and try again. Make sure there are no stray eRO client processes in Task Manager as well.