I’ve had ClickOnce blow up on me on more than one occasion and I have to confess that it really does irk me. So much time wasted on what must be a bug in Visual Studio. To be precise VS 2005 (yep I still have projects in version 2.0 of the framework).
So the problem is that after publishing the clickOnce application fails with this error:
Exception reading manifest from<fullPath and name to manifest here>: the manifest may not be valid or the file could not be opened.
+ Deployment manifest is not semantically valid.
+ Deployment manifest cannot specify minimumRequiredVersion for online applications.
I also noticed that the Updates button on the publish tab of my start-up project was disabled – tsk! So I compared the csproj file of a working project and found that the line below the PublishUrl had the value of false in it. So I changed it to true.
<PublishUrl><fullPath and name to manifest here></PublishUrl>
This fixed the problem.