Toolkit reports the backup failed because path exceeds 256 characters

This error is related to a Windows limitation call MAX_PATH, more information can be found here from Microsoft.

To help resolve this issue, Toolkit version 1.3 introduced a new Report functionality. To verify you are running the latest version of Toolkit, quit Toolkit from the system tray and start it back up, or reboot your computer. Toolkit will automatically update to the latest version.

To check the version number:

Click the Gear icon in the upper right
Click About
The versions will be listed on that screen, note the Toolkit version

To locate the path that is causing the backup to fail:

Launch Toolkit
Click on Backup
Click the More button () on the failed backup job

Click on Report

This opens a window that displays the path(s) to the file(s) that failed to back up. Click on the file path located in the Host Path column and a window will open allowing you to rename the paths to something shorter so the backup can complete.

This process may be required more than once depending on how many paths exceed 256 characters.