问题
Our site has upgraded from Kentico 10 to K11 but due to some inconsistency upgrade was not proper finished. Site is running but I am getting error when I am Import object from another K11 instance. Error is
'dataType' argument cannot be null. Parameter name: dataType
screenshot:
回答1:
If you're upgrade completed but had errors then the upgrade was not successful and it will haunt you until you go back find the issue, resolve it and do the upgrade properly until it succeeds. Trying to import an older version of a site into a new version of a site is also not a proper way to upgrade either. I know you stated your import was from another v11 instance but if you had another v11 instance why import it into a broken version 11 instance vs use the new one?
At any rate, the key is to get the "finished" messages in the event log and to ensure your upgrade is successful before continuing to import any other sites, modules, webparts, etc.
I suggest looking in the Kentico event log and see what the specifics are about the failure. Also you might be able to post the XML from the export file which will help us be able to troubleshoot a bit more.
来源：https://stackoverflow.com/questions/48625214/kentico-import-is-not-working-after-upgrade-site-into-kentico-11-from-kentico10