These error codes are listed in the SyncBack help file under the section Command Line Parameters.
When running SyncBack from the command line, a batch file, etc. then it will return an exit code that gives an indication of whether the task was completed successfully or not. As a number of tasks can be done via the command line at the same time, e.g. import a profile, run it, then delete it, the exit code relates to the last task done on the command line. Also note that if a group profile is run then the exit code is undefined. In the list below, the second column, e.g. 0xFFFFFF97, is what the Windows Task Scheduler will show in the Last Result column.
Success, no error.
SyncBack did not close because of user interaction or the -donotexit parameter was used
The -countdown parameter was used and the user aborted it
An attempt was made to import a profile from the command line and it failed
The -export parameter was used and a profile export failed
The -delete parameter was used and the profile failed to be deleted
The user aborted the profile run
The profile name given does not exist
The profile was not run because it is disabled
The profile run failed (note that the result of a group profile run is unknown). Check the log for details.
An attempt was made to import a script from the command line and it failed
An attempt was made to synchronize with the SBM Service from the command line and it failed
The serial number is invalid or the evaluation period has expired
SyncBack is being run from an external drive and there is no write access to the folder SyncBackPro is being run from
An encryption key is being used but it cannot be loaded or is corrupt
The Ransomware Protection failed