How the installer determines if to upgrade or fresh install

[tzachk]

Hi francesco,

Which key in the regisrty is read by the installer to decide if my product is already installed and thus perform an upgrade or it isn't installed and thus perform a fresh install?
I tried deleting the entries from the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall and from HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall to see if now the installer will perform a fresh install instead of an upgrade, but that didn't work.

Thanks,
T

[FrancescoT]

Dear Tzachk,

this is resolved at package Runtime through MSI WINAPI.

By the way, I discourage you to tamper the registry at such purpose. The results can be disastrous.

Regards

[tzachk]

Hi Francesco,

I'm trying to help a client that by mistake deleted the installation folder and to make things worse he then then deleted registry keys to try to manually uninstall.
He want to perform a clean install, but the installer have issues uninstalling the product.
What I'm trying to perform is to remove the registry key that makes the installer thinks the product is installed, do a clean install, and then uninstall.

Tzach

[FrancescoT]

Dear Tzach,

you may try to use;

- a restore point to restore the machine's system files to an earlier point in time.
- Microsoft Fix-it online tool.

Hope this helps you.

Regards