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 SDKs\Windows\v7.0A\Bin\NETFX 4.0 Tools\mage.exe