No offline prompt

Is it possible that in the user settings (Adminsitration->User) that offline mode is disable for him?

No, I just checked but his user account has allow offline mode checked.

Could you take a look at the application log in Help to verify if an error happen?

David,

He erased the log, started RDM (when offline use is enabled) when connecting to SQL is possible
but then the logging remains empty.
When starting RDM when SQL server is not available the error in the log makes sense:

[1/8/2013 4:20 PM]ERROR System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
at System.Data.SqlClient.SqlConnection.Open()
at Devolutions.RemoteDesktopManager.Business.DataSources.DatabaseConnectionDataSource.GetData(String sql, IDbDataParameter[] parameters)
at Devolutions.RemoteDesktopManager.Business.DataSources.SQLServerConnectionDataSource.GetDataSourceSettings()
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.LoadDataSourceSettingsFromDataSource(BaseConnectionDataSource newDataSource)

Could you verify if in %LocalAppData%\Devolutions\RemoteDesktopManager you see a .sec file? If it's there, could you try to delete it?

No, still no prompt.
I even copied over my own entire folder including the config file and even that does not cause the offline question to come up.
Couldn't this be some kind of reg setting?

So there is no .sec file?

Yes there was a .sec file, he removed it. Then restarted RDM, with no offline message.

Delete the file .off as well

Whatever we try, the offline use will not work.
Even tried to install from scratch on this computer...

Let's summarize,

1. the .sec file is here and it is re-created when you delete it
2. you use the latest version (8.0.12.0)
3. if you create a data source with your own credentials, does it work?

I will summarize today:

I removed everything.
Then I downloaded 8.0.12.0.
Configured the datasource.
Then when using a sql admin account the offline question pops up.
When checking the security users I noticed that the users their did not match the SQL accounts.
Changed it and it is working.

Thanks for helping!
Cheers!
Sjoerd