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Reinstalling MDAC

Microsoft Access Data Components are usually fairly stable. They tend to be updated with significant OS related updates (I'm looking at you, Service Packs). 

That being said, issues do happen. Today I encountered an issue following a P to V migration using Hyper-V for a Windows 2000 server with an ADO connection to a MSSQL database. Somehow MDAC versions become mismatched during this process.

Your actual error may vary. Your application may throw an error 429 "Active-X component can't create object", you might get a IPP_E_MDAC_VERSION error. In the case today, a line in the website's general.asa was mentioned as an invalid object.

Download and execute the Microsoft Component Checker to verify a mismatch against your required Component versions - Use this for 2003 and this for 2000.

For Windows Server 2003 and 2008 systems, I would typically advise an in-place upgrade as outlined here. You can try a manual install on these OS' but frankly it is not as reliable as an automated repair (or an SP update, if one is available). Once I have enough time to creatively break Windows Server 8 I will hopefully update accordingly.

For Windows 2000, your task is of course a bit more painful. Download the appropriate installer from Microsoft (this is for MDAC 2.8 SP1 - I've tested up to 2.8 using Server 2000 and SQL 2000 and it works, usually the issue is one of your files are older than anticipated by MDAC, going newer hasnt hurt me yet, and is the latest confirmed as working by Microsoft). A formal compatibility list is also available.

After installing and rebooting with Mdac_typ.exe, reboot and your components should now once again be compatible. The most frequent issue I have seen is as the result of running the utility in a non-Administrator account, which leaves out key registry components. Regmon is a bit outside of our scope for this late-night post, but we will get to registry permissions hacking in later posts.