1 reply to this topic

[clareb22]

I'm hoping someone will have an answer to a question that I have been asked.  We deal with third party product e.g. licensing software that must be installed with our products, but as a third party vender there may already be other products that have this installed on a client machine.  Does a merge module check for third party installs of this or just installs produced by us, even if they are not installed using a windows installshield installer?

[Ian Blake]

Definitions
1st Party - You
2nd Party - Your customer
3rd Party - Owner of shared software
4th Party - Anybody else.

If the merge module has been supplied by the 3rd party then the component guids will be the same for  both you and a 4th party.  So the first installed components will be used (or upgraded if required),

There is a danger when you and a 4th party create merge modules or include 3rd party software directly in your products because you will use conflicting  component guids which will cause problems when thay are both installed/removed on the same machine.

It is quite wrong for a 4th party to publish a merge module for something because it will mess up the 3rd party's distribution and any other 4th party solution.

The main reason for the existance of merge modules is so that 3rd party manufactures can ensure that their products are distributed in a safe and well strucutured way.

The 4th party merge modules from InstallShield for things like DCOM or MDAC are not proper msi merge modules.  They are simply wrappers for a legacy install program, so they are no more dangerous than the legacy installs themselves.

I believe it is always worth contacting the 3rd party supplier and explaining the need for a merge module.  You never know they may have one.

I you need to supply the 3rd party files directly then make sure you set the shared attribute.  It may save you from some nasty surprises.