ClickOnce deployment and customHostSpecified error

Some time ago now I wrote about doing manual ClickOnce deployment using the command line and FinalBuilder. One of my readers posted a reaction about the following error.

The customHostSpecified attribute is not supported for Windows Forms applications.

I did not have that specific error at the time, and the reader didn’t follow up on my reactions. But now I had the problem myself. Luckily I found the answer pretty fast. I used the old version of mage.exe from the .NET Framework 2.0 SDK. I needed to use the .NET Framework 4.0 SDK mage and my problem was solved. You can find that version right here:

C:Program Files (x86)Microsoft SDKsWindowsv7.0ABinNETFX 4.0 Toolsmage.exe