I had to impelement a MSSQL-Server 2016 with asynchronous mirroring.
So I followed every step written in several tutorials (like Restoring with NORECOVERY before Mirroring etc.). It seem that sthg was missing because I always got the Error 927 which means cannot access database because it gets restored… Seems logic but for Mirroring-Setup Database have to be in NORECOVERY State (means its not accessible and state is „restoring“).
After several days of re-installing, researching i finally solved it, with installing Microsoft SQL Management Studio 2014. I did the same as before and it worked without a problem.
The MSSQL 2014 Management Studio Installation should be here https://www.microsoft.com/de-DE/download/details.aspx?id=42299