I am looking for a replacement for InstallShield. Unfortunately we only have 1 license for InstallShield and it was installed on a developer's machine. I'm considering switching over to WiX, but after reading the documentation there is a Product ID GUID, Upgrade Code GUID and a Package GUID.
I also know GUID's were created by InstallShield. If I switch over to WiX can I start using new GUID's or do I have use some of the GUID's created by InstallShield? If an upgrade to a product is released will switching installers hose customers who had the old installer?
In order to be able to upgrade your old package, you need to use (and find out) your old upgrade code.
The Package code should be different (ie autogenerated) for every different MSI (the MSI can be cached with the guid as cache key).
The Product code should be different between major upgrade, but is important for minor upgrades and patches. I haven't used wix to do anything else than major upgrades right now, so I don't know the exact details
See the MSDN article on patching and upgrades as well as the WiX Tutorial
It may also be interesting to know that you can decompile the msi that was generated by Installshield with the dark.exe tool (included in wix). This will recover the upgrade code among other things.
I'd also suggest getting a copy of The Definitive Guide to Windows Installer, I highly recommend the book and don't know how I would have migrated to WiX without it. It's a very low level overview of Windows Installer, if you understand the book then WiX becomes pretty easy.
I know you've already accepted an answer, but make friends with Orca if you haven't already done so.
Orca helped me understand MSI and what WiX was doing under the covers. In your case it would make finding the Upgrade (or any) GUID very easy.
This question may also save you some time and headaches :)
来源：https://stackoverflow.com/questions/591186/switching-from-installshield-to-wix