ClickOnce Root Element Missing

This is somewhat related to this thread:

https://www.vbforums.com/showthread....or-Suggestions

but only in that this problem is what started the whole thing. I'm inclined to say that this is not strictly a ClickOnce problem, and might be hardware, but I'm just not sure.

In that other thread, I was having issues installing an application using ClickOnce. As far as I can tell, that program is installing correctly on every computer aside from one. It was the inability to install the application on that one computer that got me looking at the application installation, but I was able to get it installing elsewhere. It STILL isn't installing on this one computer, though.

Installation goes through the initial steps, then fails with a message about an unhandled exception during startup: An error occurred creating the form. The error is: Root element is missing.

Now, the first part of that is probably meaningless, because any number of unhandled exceptions could occur during startup, so it is probably just that "Root element is missing." part that matters. A search on that results in a variety of answers, none of which seem applicable.

XML requires a root element of some sort. If it is missing, it is missing. I don't know exactly which XML file is the problem, in this case. The application manifest (.application file) is XML, but if that were bad, I think the error should happen VERY quickly, and what actually happens is that an animated graphic pops up at the start of the installation (not something I created, but something related to either Windows or ClickOnce), and only after that does the error appear. That suggests to me that the .application file isn't, itself, the issue.

Furthermore, I have installed the application successfully on some other computers, by now, so it does appear to work. The people who had this computer told me that they didn't trust it already, because it appeared to behave oddly at times. I'm not sure what that means, but it's suggestive.

I am inclined to believe that the XML is not missing a root element. If the files were simply bad, then the application would fail on ALL computers, but it only fails on the one. One thing I found suggested that there could be something wrong with the Byte Order Mark, possibly due to encoding. The encoding looks okay, and likely is. Could some errant setting on the computer in question mess up interpretation of the Byte Order Mark?

Any other suggestions of what to look at, how to further investigate, or anything else related?

Don't use ClickOnce myself but found this which might help https://docs.microsoft.com/en-us/vis...s?view=vs-2022

Quote:

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Originally Posted by bmwpete

Don't use ClickOnce myself but found this which might help https://docs.microsoft.com/en-us/vis...s?view=vs-2022

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Yeah, I've seen that page. I was unimpressed. I realize that they're just guessing at which errors might show up, but it's hardly an exhaustive list of what could go wrong.

Thought that using the 'How to:Specify verbose log files for ClickOnce deployments' would help?