The server for a Nav 5 implementation that I am working on crashed about a month ago. A new windows 2012 r2 server was created and NAV restored. Several hundred users were added by an administrator, about 700 I think - users dating from 10+ years ago, even if they aren't there now - at that time the syncing worked fine he said.
However, as of two days ago they are getting the message mentioned in the subject - but the fact is that the user does actually exist on the sql server.
It happens when either a) the admin goes and adds a new user in NAV / database user and also adds the matching user in SSMS, and then goes to "Sync All'
or b) it seems to be happening starting with users beginning with 'a' - in other words I think it is not finding ANY user that is listed in NAV database user list in SQL Server, even though they are in SQL Server.
NAV is a published Citrix app, I don't know if that is relevant.
Windows security update kb4493446 was installed 5 days ago - doubt it's relevant but just mentioning it.
i am adding some info to this. I am still working with the client to figure out the history of what was done after the crash. What he told me today was that after the crash he rebuilt the users lists and all the users started working. He didn't do a sync all as I had previously thought. However, the problem is when he goes to add new users individually. He adds the sql user, then he adds the nav database user and when he adds the nav database user it gives him the error in question - even though the sql user is there. However, today he says that one of the users that he got the error on, even though it gave the syncing error, that user was actually able to go on and get in and start working. Now he added another user and it gives the syncing error - I will find out if the user is actually working in spite of the sync error.
Does this help or shed any light on the problem?