If you’re using linked tables from MS Access to a database server (Oracle or SQL Server) using the MS Access GUI you can simply put a check mark in the ‘Remember password’ box. If you’re dynamically creating linked tables from VBA and supplying the username and password in the Connection member of the TableDef object then Access will still prompt for credentials when its restarted.

You can avoid this by using the dbAttachSavePWD attribute. Example:

Dim tDef As TableDef
Set tDef = CurrentDb.CreateTableDef("MyNewTable", dbAttachSavePWD)
tDef.Connect = ...
tDef.SourceTableName = ...