For the last day or so, we’ve been working on rolling out the next release of our code to our QA environment. When it came time to build a new set of solutions I stumbled across a weird validation error.
An error occurred while validating. HRESULT=80004005
This error popped up on the setup applications for several new programs. Doing some searching I stumbled across a couple of posts that hinted on removing the project output from the setup, and trying again. This stopped the errors on the setup application, but not the actual application itself.
Then I saw a hint in the errors list…
Application Configuration file "App.config" is invalid. '-' is an unexpected token.
Checking into the app.config file, I stumbled across the cause. It looks like somebody had pasted code that had been “fixed” up by Outlook, or word, and broken a comment. Fixing this, resolved both the app compilation, and the setup validation error.