patch on top of patch on the same product not working

I installed my product named XYZ.msi. Then, I created a patch (patch1.msp) and applied that patch on my product and it worked fine. I can also see the changes in the Add/Remove Programs.

Then I created another patch (patch2.msp) for the same product (XYZ.msi) and when I double clicked it, it says "The 开发者_JAVA百科program to be upgraded may be missing". I don't understand this when I apply patch2.msp on XYZ.msi without applying patch1.msi first it works fine but applying both patches doesn't work.

I am making patches through Windows Installer SDK through msimsp.exe by patch.pcp file.

This happens because your patches are not authored correctly. A patch shouldn't change the ProductCode or UpgradeCode. It also shouldn't remove components or features from the original installer.

You can read more about the patch authoring rules here: http://msdn.microsoft.com/en-us/library/aa367850(VS.85).aspx?ppud=4