I just migrated a site for the second time and got the same problem, 'Restoring database' went on for several hours and never completed. I tried doing the standard solution, wait 15 minutes and open the admin in another tab and received a 500 Internal Server Error - the error log reads - 1461918129: /hermes/bosnaweb04a/b310/ipw.theragpl/public_html/snap/ssv3_payload_extractor-rdqhMEwlDT.php startup
I checked the MySQL database and it appears the database files all migrated over but I can not bring up the site or admin at present.....only receive the Internal Server Error.