I am not sure why you have not named what the plugin is - it is critical information relating to the problem, so please be kind enough to name the plugin.
That shouldn't matter.
The plug-in is an OFX plugin called Transition Master that doesn't work in Vegas and isn't designed to but works in other software that I need. So I need it installed on my machine in the common plugins folder. I do not need it to work in Vegas nor do I expect it. I expect Vegas to launch though even if it encounters an OFX plugin not designed for Vegas
The problem is that there needs to be a way to tell Vegas not to try to load this plugin.
My system is Windows 10.
I seem to remember being able to disable specific audio plugin VSTs within Vegas when Vegas wouldn't startup because it couldn't load them. What I'm looking for is that option for OFX plugins.
Further, Vegas should not crash because it can't load a 3rd party plugin. It should just skip over the plugin and not offer it as an option in the software. It's ridiculous that I can't even start Vegas.
Please list the folder path to your Vegas OFX Plugins.
Please list the exact folder path to your offending plugin. Are there other plugins in that folder that also try to load in Vegas, once you have disabled the offending plugin? Do they cause a crash at startup? Are there others you do not recognize showing in this window?
Contrary to your impression, rogue third-party plugins happen all the time. Vegas is not always able to trap them before the fact. Your best bet is to make a detailed problem report -- and submit it to the developers of that third party plugin.
I suspect you have it installed in a Common Files folder that Vegas scans at startup. until then, you can try reinstalling it in a different, dedicated folder, or renaming as you are doing now.