I encountered the same problem of Dave_McLaughlin, exactly the same errors when loading any solution after installing the TinyCLR OS Project System extension.
Originally VS2022 was working correctly, I think the problem started with TinyCLR OS Project System extension 220.127.116.1100 or 4200 (I’m not sure on which one).
I currently use VS2019 (with TinyCLR OS Project System extension V2.1.700) and I can debug solutions with TinyCLR Libraries and firmware V18.104.22.16800 and everything works: any TinyCLR solution, regardless the TinyCLR version used, loads correctly, the same for non-TinyCLR solutions.
I completely uninstalled VS2022, cleaned up everything (using C:\Program Files (x86)\Microsoft Visual Studio\Installer\InstallCleanup.exe to remove any VS entry both in the file system and the registry) and reinstalled it.
Just after the reinstallation, non-TinyCLR solutions load correctly.
After installing the TinyCLR OS Project System extension, I get the same errors as the ones described by Dave, even when trying to load a not-TinyCLR solution!!!
If I open the VS2022 IDE without code, I don’t see the the TinyCLR OS Project System extension in the Extensions Manager, and if I try to create a new project the TinyCLR OS platform is not listed, so I think there is a problem in the extension installation procedure that fails even if it says that the installation has completed.
I searched the web and I didn’t find any clue on how to solve this problem.
“After you created project on 2019, if you want to use VS2022, you need to uninstall TinyCLR Core 2.1 and install Core 2.2. You need to uninstall, clean project, delete packages folder… not just delete or remove from explorer window.”
Can you please be more detailed on this? About TinyCLR Core 2.1 or Core 2.2 I think you refer to the SitCore firmware, but the problem comes before connecting the SOM. The problem appears before connecting the device.
I remember that before encountering those errors (with the previous extension version I guess), I used to open the TinyCLR solution both with VS2019 and VS2022 with no problems.