Addin settings fail to work on other machines

[RogerAsbury]

I've been working on an addin for some time and decided it needed some settings. I created a .settings file and associated backend c# files to utilize it and it works great on my development computer. But when I deploy it to others, the settings don't load. The image below shows what should show up on the left side and works fine on my computer. On the right, when you click the FNSB Addin Settings text on another computer, it just sits there with a spinner forever. It never seems to crash out, you can click Cancel to get out of it, but never loads. Attempting to use anything that relies on those settings does eventually crash.

Left: Working - Right: Just a spinner. 😞

Any ideas what may be going on here? Attached is the autogenerated code behind the settings file as generated by Visual Studio 2022.

Edit - Figured I'd add a system profile here, if that might help. Both systems running Windows 11. Top profile is the working system, bottom system the non-working one.

[RogerAsbury]

Considered adding this as another edit to the main post... Chose to add as additional post just in case.

Thought it might be that the app wasn't finding the user.config, but I can confirm that not only can it find it, it can write to it. One of the things I do is add a "started at" kind of message to a log that is kept in the user.config file (probably not the best of ideas, but at least I give the user an option to clear it) and it is definitely appending to that log...

        <FNSBArcGISProAddin.FNSBAddin>
            <setting name="LoadLog" serializeAs="String">
                <value>9/25/2025 9:22:36 AM FNSB ADDIN Started.

9/24/2025 3:09:52 PM FNSB ADDIN Started.

9/24/2025 3:04:17 PM FNSB ADDIN Started.

9/24/2025 3:02:47 PM FNSB ADDIN Started.

9/24/2025 2:58:17 PM FNSB ADDIN Started.

</value>
            </setting>
        </FNSBArcGISProAddin.FNSBAddin>

This just leaves me a bit more confused on why it's not loading in the Options panel. 

[RogerAsbury · Accepted solution]

Solution found here:
Solved: My custom application settings page does not load,... - Esri Community

In a nutshell: Settings must have default values.