Clickonce error: missing files. Need to get missing filename

Question

My ClickOnce app gives an error for a user: "Cannot download the application. The application is missing required files. Contact the application vendor or your system administrator for assistance."

How can I pinpoit which file is missing? Do I manually need to put files on the publishing server?

I thought when I click on the prerequisities and set the option to download the prerequisites from the component vendor's web site and set to include components, ClickOnce would include all of them. Looks like I am missing something. How do I know what it is. Manually going through the manifest is going to be time consuming.

Answer 1

What I usually find on these issues is it's related to a dependency that is set as "Include (Auto)" instead of just Include. It will work on some machines but not on others just depending on what DLLs are already installed on the destination machine.

Files to include Open up the Publish tab of your project properties and click on the "Application Files" and then inspect which DLLs are set to "Include (Auto)." You may need to change some of them to the standard "Include" for things that are installed into the GAC on your machine. Visual Studio will make some assumptions based on your machine's configuration.

Log File Another thing to check is usually the error message will reference a text log file. I don't believe it links it in any way so you'll have to browse out to it. But find that file and it should give you some more information.

Certificate Errors One problem that I have seen is if the SSL certificate that is installed on the server is not trusted on the machine you are attempting to install it on. I find this often for the GoDaddy SSL certifications since they are not always installed on machines who don't frequently use Windows Update.

Answer 2

ClickOnce is famous for displaying errors that have no relation whatsoever to the actual problem. If the problem is confined to a single user (which is what it sounds like), I typically first try clearing out the user's ClickOnce cache by deleting the %user_profile%\Local Settings\Apps\ directory. This will solve 80% of those "Contact application vendor..." errors and is relatively low impact on the user's PC. They will simply have to re-download all of their .NET apps.