Add missing file with msp patch

Question

I created an installer, deployed to our test environment and got an error due to a missing dll (it was not included in the wsx file). Is it possible to create a MSP patch to ship the missing dll or is it better to simply create a whole new installer?

I tried following various examples but I keep getting this error:

DEBUG: Error 2356: Couldn't locate cabinet in stream: media1.cab.

Answer 1

A patch can do anything an updated MSI can do, but it is merely a packaging and delivery mechanism that delivers an update in a more compact way. Hence you must actually create a full new version of your setup to be able to then package this new update as a patch.

Important: spend no time at all testing a patch before the full upgrade is working properly. This is a complete waste of time. It creates only mysterious errors and is a very common real-world time drain.

Unless your previous setup has gone to production and hence is "out in the wild", I wouldn't waste my time with a patch. Patches require a lot of time to create and even more time to test - there is a lot of added risk and complexity, and it is only intended to be a convenient way to deliver small updates such as what you describe without having to distribute a potentially huge, new MSI file. It is not common to use patches for UAT or QA testing unless your product is really huge and takes ages to install.

Personally I feel that MSI has failed entirely when it comes to patching. It should be an easy to use, value added feature, but it has become a hugely complicated, problematic issue in its own right.

Answer 2

Yes, you can add a missing file through a patch. Perhaps this article will help: http://wix.sourceforge.net/manual-wix2/patch_building.htm

When creating a patch you should always modify your existing installer. You don't create a new installer from scratch. Also, never remove resources from the new version. For a patch you should either modify or add resources.

Regarding error 2356, it seems like the original installation is somehow corrupted. You can try repairing the old version before applying the patch on it.