Create a FreeFileSync batch file using "silent mode".
Set error handling to "Exit with Returncode < 0" or "ignore errors" to avoid having a popup stop the program flow. In case errors occur FreeFileSync will abort with a returncode < 0 which can be checked via the ERRORLEVEL batch command.
Create a *.cmd or *.bat file to specify the location of FreeFileSync.exe and pass the name of the FreeFileSync batch file as first argument; e.g.:
C:\Program
Files\FreeFileSync\FreeFileSync.exe C:\SyncJob.ffs_batch
if not
errorlevel 0 echo An error occured! && pause
Instead of displaying "An error occurred!" you can specify any other command like sending an email notification (using a third party tool).