windows installer - WiX "Major Upgrade" doesn't completely install app on downgrade

Question

Currently all upgrades work fine whenever updating to a newer version number, however I'm getting an odd behavior when downgrading. It seems that it'll uninstall the existing version and then partially install the version that I'm trying to install, the main exe doesn't exist in the target location yet, but advertised shortcuts are created. When the advertised shortcut is opened, it'll finish the installation (presumably do a repair) and then it'll run fine.

Does anyone have any ideas why this is happening?

My upgrade block looks like this:

<UpgradeVersion Minimum="0.0.0.0" Maximum="99.0.0.0" Property="PREVIOUSVERSIONSINSTALLED" IncludeMinimum="yes" IncludeMaximum="no" IgnoreRemoveFailure="yes" />

(The IgnoreRemoveFailure was an attempt to fix this issue, but it doesn't appear to have done anything)

In my InstallExecuteSequence I have <RemoveExistingProducts After="InstallValidate" />

Also I have Product Id="*" and Package Id="*"

The reason the downgrade is needed is because the client application needs to be running the same version as the server to ensure compatibility, and the entire process needs to be automated so if the client/server versions don't match on signin the user can just click "yes" and the proper version is downloaded, installed and started. This is working so far for upgrades, but for downgrades an extra unintuitive step is needed which is to relaunch the app manually and then see a windows installer dialog pop up before it launches.

The end result is that regardless of upgrade or downgrade, the current version needs to be fully uninstalled and the downloaded version fully installed, so if there's another way to accomplish that, that'll also be a good answer.

Answer 1

This is what worked for me:

<Wix ...>
  <Product ...>
    <Property Id="REINSTALLMODE" Value="amus" />
    <MajorUpgrade AllowDowngrades="yes" />