I have a two-file database with an interface file and data file. The user logs into the interface file while the data file is set to open using a specific account and password (in the File Options settings). The users have an account in the interface file but not the data file. This works fine except every time someone opens the database FMSA 9 generates an error message in the Event.log: "Warning 661 Client Authentication failed..."

This happens both on my MacBook Pro running Tiger and our Xeon server running Leopard.

According to the FileMaker Knowledge Base Answer ID 6785 "if you have the File Options for a file set to log in using a specific user name and password you will not get this warning." Is this not true? Is there a way to eliminate this error message?

I get the same error messages in the log, even when authentication is successful. Also, I note that there are two entries in the log for each authentication. The first lists an authentication error using the account "Admin," and the second lists an error using the account that actually authenticates successfully.

I am dealing with the same issue in a new install of Server 13.  Anyone successfully deal with this 661 error message issue?

Typically it is because the file is set to auto-login in File > Options

In this case, it appears to be the "opener" file that we use - it had "admin" in the file option account field, and therefore was trying to use that every time anyone opened a DB.  Looks like I'm on the right track now.  Thanks Wim for the input!