If you are encountering this error, the tool itself won't fix it—you have to do it manually. Here is the solution that resolves the issue in 90% of cases:
For brand new installations, the background service may fail to register correctly with Windows. This causes the folder access handshake to time out. 3utools failed to access folder error code 13 new
: Temporarily disable third-party security software or add 3uTools to the exclusion list, as these can block the software from writing to system folders Apple Support Community How to fix 3utools error codes on any iOS device If you are encountering this error, the tool
If none of the above work, your installation is corrupt at the ACL (Access Control List) level. : Temporarily disable third-party security software or add
If you don't want to turn it off completely, click "Allow an app through Controlled folder access" and add 3uTools.exe and iTunes.exe manually. However, for flashing firmware, turning it off entirely is recommended.