What is the best procedure for installing or upgrading MDAC?
As with all product upgrades, you should test to verify that existing applications work as expected with the upgrade before applying it to production systems. Adopting a proactive installation and upgrade strategy is the most effective way you can avoid rollbacks. If you first upgrade a test system with a configuration identical to the production system, you can identify potential issues and avoid the hurdles associated with a rollback. To ensure a successful upgrade, identify issues with an MDAC upgrade before committing it to production systems, and alert Microsoft Product Support Services (PSS) to any problems as early as possible in your development and deployment cycle. As with any system upgrade, if you are unable to implement it on a test system, you should have a comprehensive backup or disk image of your production system as well as a complete recovery plan.
