1308 - ESE: Error "Backup failed: Illegal character"

Symptom

A backup fails with the following error:

ERROR : 12:50:56 Backup failed: Illegal character ((CTRL-CHAR, code 0)): only regular white 
space (\r, \n, \t) is allowed between tokens at [Source: (byte[])" "; line: 1, column: 2]

Cause

This is usually caused by a corrupt file in the local cache of the backup history configuration files,

Solution

1. Stop the ESE service.
2. Delete the history directory in the working folder.
   • The default location for the working folder is C:\ProgramData\Redstor Pro\Backup Client ESE\data\history. If the folder resides in a customised location, this can be viewed in ESE under Options > Advanced > Working Folder.
3. Restart the ESE service. This should resolve the issue with no loss of data. The history directory will be repopulated from the cloud version whenever a previous backup date needs to be accessed in this circumstance.