The return code from Robocopy is a bit map, defined as follows:

    Hex   Decimal  Meaning if set
    0×10  16       Serious error. Robocopy did not copy any files.
                   Either a usage error or an error due to insufficient access privileges
                   on the source or destination directories.

    0×08   8       Some files or directories could not be copied
                   (copy errors occurred and the retry limit was exceeded).
                   Check these errors further.

    0×04   4       Some Mismatched files or directories were detected.
                   Examine the output log. Some housekeeping may be needed.

    0×02   2       Some Extra files or directories were detected.
                   Examine the output log for details. 

    0×01   1       One or more files were copied successfully (that is, new files have arrived).

    0×00   0       No errors occurred, and no copying was done.
                   The source and destination directory trees are completely synchronized. 

You can use this in a batch file to report anomalies, as follows:

    if errorlevel 16 echo ***FATAL ERROR*** & goto end
    if errorlevel 15 echo OKCOPY + FAIL + MISMATCHES + XTRA & goto end
    if errorlevel 14 echo FAIL + MISMATCHES + XTRA & goto end
    if errorlevel 13 echo OKCOPY + FAIL + MISMATCHES & goto end
    if errorlevel 12 echo FAIL + MISMATCHES& goto end
    if errorlevel 11 echo OKCOPY + FAIL + XTRA & goto end
    if errorlevel 10 echo FAIL + XTRA & goto end
    if errorlevel 9 echo OKCOPY + FAIL & goto end
    if errorlevel 8 echo FAIL & goto end
    if errorlevel 7 echo OKCOPY + MISMATCHES + XTRA & goto end
    if errorlevel 6 echo MISMATCHES + XTRA & goto end
    if errorlevel 5 echo OKCOPY + MISMATCHES & goto end
    if errorlevel 4 echo MISMATCHES & goto end
    if errorlevel 3 echo OKCOPY + XTRA & goto end
    if errorlevel 2 echo XTRA & goto end
    if errorlevel 1 echo OKCOPY & goto end
    if errorlevel 0 echo No Change & goto end
    :end