If you don’t change the version number of your .NET project output every time you create a setup package, you may have found that it’s difficult to have the Setup program reliably uninstall the existing version of your software before installing your update.

Here’s how to add a batch file to your setup project to accommodate this.

First, left-click to select your Setup project in the Solution Explorer, and copy the “ProductCode” field’s value (it will be a GUID) from the properties window (if you don’t see it, hit F4 to bring up the properties listing).

Next, right-click your Setup project and choose Open Folder in Windows Explorer.

Create a file there called RunMeToSetup.BAT with the following content (substituting the GUID below with the one you copied):

MsiExec.exe /uninstall {00000000-0000-0000-0000-000000000000} /qb!-
"%~dp0setup.exe"

Save the batch file.  Then go back into Visual Studio.

If your Setup project is under source control you may have to right-click it and do “Check Out for Edit…” prior to completing the next step.  (If it is not, dude WTF?)

Right click your Setup project and choose Add… File… and add the .BAT file.

Then select the .BAT file  in the list and hit F4 to show the properties window for it.  You need to change the “PackageAs” property to “vsdpaLoose” which is the non-intuitive way of saying that this should be copied into the installer directory, but not zipped up into the MSI.  (Stay classy, MSFT!)

Then when you right-click and build your Setup project, the output will be the setup.exe, the MSI file, and your new batch file.  When you double-click the new batch file, it will run a “bare” uninstaller first for your application’s GUID (non-interactive UI), and then run the setup program.  The crazy %~dp0 thing is just to work around the command-line not fully understanding UNC paths as a starting point (if you double-click the batch file starting in \\myserver\myshare, the “%~dp0setup.exe” will resolve to “\\myserver\myshare\setup.exe”).

If you wish to customize the uninstaller behavior, you can find the switches that MSIEXEC accepts here:  http://msdn.microsoft.com/en-us/library/windows/desktop/aa367988(v=vs.85).aspx

Once you test this successfully on a VM or however else you test your install software, check your setup program and the new batch file back into source control.