Continue the previous chapter, the authentication mode after the conversion will continue WSS_Content restore the backup to 2016 database server upgrade, or find an error, error shots are as follows:
View the log, referred to also experience some site collections or 2010, you need to upgrade, but obviously I upgraded it, or before a certain cause of those warnings.
Of course, when at the beginning of this project was supposed to resume personal website, personal website is for each site collection, but later due to the customer's environment lead to personal website up and useless, since it is useless, old vintage stuff, no data need to back up directly to these sites all set delete it.
Then tackle the most important collection of sites we use PWA.
Because it is webpart, Features, Setup File, Event Receiver not, so these need to be deleted from the page.
Intermediate found a lot of information at the following link:
https://social.technet.microsoft.com/wiki/contents/articles/31302.sharepoint-2013-troubleshooting-the-migration-issue-missingwebpart-webpart-class-is-referenced-1-times-in-the-database.aspx
https://www.sharepointdiary.com/2016/01/remove-web-part-from-all-pages-in-sharepoint-site-using-powershell.html
https://blogs.technet.microsoft.com/dawiese/2017/05/09/post-upgrade-cleanup-missing-server-side-dependencies/
http://www.boostsolutions.com/blog/how-to-remove-missing-webpart-during-sharepoint-upgrade/
Finally, still did not solve the problem, powershell did not delete the data in the database is deleted, and finally no way to manually delete the database data.
Get!