Deployment: Side by side install causes "another version of this product is already installed" error
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When deploying a C# Windows Service the following error message is encountered:


> “Another version of this product is already installed. Installation of
> this version cannot continue. To configure or remove the existing
> version of this product, use Add/Remove Programs on the Control Panel”

**Now the problem is that we actually do want 2 instances of the same service and version deployed.** 

In this case each service does the same thing for a customer that distributes 2 different brands. Rather than creating a multi-tenant application it was easier to just sell an additional license to an existing product. 

So my questions: 

1. Is the only way to get around this to alter the GUID for the product code of the service? 

2. If so how can this been done automatically so I don't have to rebuild on each deploy? This error message kicks in prior to the install wizard so using custom screens during installation is not an option to solve this problem.

