Are you entering the name of the instance when you log in to Management Studio (see attached)?

What about the rest of my suggestion?

Go back to your primary and check that the backup job is running. Open the folder and check that the file is being placed where you expect. Basically, kick off...

Sorry; I even switched browsers, and the duplicates keep happening.)

Is the guest user definitely enabled for master?

Yes, that's what I'm saying; state 38 means 'Login valid but database unavailable (or login not permissioned for that database)'.

http://sqlblog.com/blogs/aaron_bertrand/archive/2011/01/14/sql-server-v-next-denali-additional-states-for-error-18456.aspx

It sounds like they're trying to connect to a database that doesn't exist, then. Are you auditing failed logins? If so check what it says in the SQL log. (Sorry...

Related to this, if you check the permissions in the master database, has anybody removed access from the public role? It should be there, with a tick under Grant ...

Ok, on the login dialogue box, under Options can you get them to specify the database name (by typing it in, not browsing for it)- see attached- then clicking Connect?

Thanks. It's really hard when you can't just see the instance in question :-D.

So are you saying that if you untick Sysadmin under Server Roles and save it, this prevents...

Fingers crossed it works!

(Dup!)

Posted too soon!

They log into SSMS as DomainName\Username yes? If you check under Security > Logins > DomainName\Username right-click, Properties, what have they got under Server Roles? And what...

No, a login, not a role. I'm trying to think how to phrase this;

Can you put the whole of that error message up here? The one that starts 'Could not find a log backup file that could be applied to secondary database'.