I updated my InDesign CC application to 2022 yesterday, and was able to work on my file (after the update) just fine. I guess that my computer had apparently restarted overnight, because now I get the "InDesign might not support the file type, a plugin is missing, or it may be open in another application" message whenever I try to open it. It is not happening with any of my other files, only this one. The file, when I look at its properties, is listed as an InDesign 2022 document, which matches up with my InDesign 2022 application. I have only been working on it on this computer and in InDesign ONLY, and I have restarted my computer (and InDesign) multiple times. I have no idea why this is happening.