Why is everything so complex to get going with Wix, then so easy in the end when you get the syntax correct?

If you want to allow your MSI installer to upgrade a previous version then there are some things you have to have correct if you don’t want the ‘Another version of this product is already installed’ dialog appearing.

  • The Product Id should be set to * so that a new Guid is generated each time the product is rebuild
  • The Product UpgradeCode should be set to a fix Guid for all releases
  • The Product Version should increment on of the first three numbers, by default the final build number is ignored for update checking
  • The Package block should not have an Id set – this will allow it to be auto generated
  • You need to add the MajorUpgrade block to you installer

So you end up with

Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:netfx="http://schemas.microsoft.com/wix/NetFxExtension" xmlns:util="http://schemas.microsoft.com/wix/UtilExtension" xmlns:iis="http://schemas.microsoft.com/wix/IIsExtension">
    <Package InstallerVersion=“405” Compressed=“yes” InstallScope=“perMachine” InstallPrivileges=“elevated”  />



So simpler than pre Wix 3.5, but still places to trip up