Chris,this can't be easily fixed. While there is something that is called "multi-instance support" in MSI itself, the tools support is weak, and one needs to put some bootstrapper exe on top of the MSI.

if you replace upgrade with another instance, then how you upgrade ?

You can definitely have multiple services in a single installation, and this is what mysql_install_db.exe does. Why would you like to have multiple instances of older and newer exes.

If you're wondering why 32 and 64 bit versions are installable on the same machine, it is because I gave them different GUIDs. Which means, technically they are treated as different products.

> Why would you like to have multiple instances of older and newer exes.

I only do this because I test so many different versions, and like to have at least one of every version installed. And in this case, I was just trying to compare 2 of the same major version, but differing minor versions (and I was being lazy by trying to use the installer for both instances - as I generally run no-install versions for such tests).

I see your points though. I thought if perhaps it was very simple, then it might be worth adding (if it was a single check), but since not, it really doesn't make sense to implement this. Further, I can't really envision many, if any, aside from Support Engineer-types who use Windows ever wanting this - which I'm gonna go out on a limb and say is a small number.

Feel free to close this off.