We are planning to change the authentication provider from claims-based authentication to classic windows mode. I am planning to do this by preserving the content databases and re-create the web-app with the new authentication. Can anyone tell me how to migrate the users to the new authentication i.e. relinking them with the previous identities on security groups and/or their documents? Any suggestion to do this in a better way would be great as well.
There is a command in PowerShell under a SPWeb object called MigrateUsers. But tbh im not sure if it works the other way, setting it true converts users from classic to claims. One should think setting to false would do the opposite. But I haven't tested it.
Using the Move-SPUser command with a powershell script should do the trick.
Something like this