I am having issues too – sometimes it has to do with disk space at your current provider or bandwidth allotment. I have fixed issues with migrator before by changing disc quota on my current hosting provider (hostgator) I am having issues with one of my domains now that I can’t seem to resolve -supposedly there is somewhere to check a log file -i haven’t found it yet
Update – I am rerunning the migration plugin – hoping for no errors.
mine was giving me critical error – so then I deleted the site on siteground and started over -gave me critical error again. I wound up clicking on the siteground migrator plugin icon and it showed to still be transferring in spite of having given me an error. Now I show it complete.
I had changed the bandwidth and size … but still had the error – all good now it is transferred -hope yours worked too
I tried again and I got a different error, but then I received an email that the transfer was successful…(?!).
Glad yours worked too!