Resolved Unity Hub 2.4.2 No Longer Opening Projects and Can't Update License?

So, I've started running into a lot of bizarre Unity issues the past few days, following a few software updates. The specific issue I need help with, is that I can't seem to open any projects that are below version 2019.4.16 through Unity Hub.

What's happening, is that I try to open a project that's using Unity 2018.2.11f1. I see the splash image appear for maybe 5 seconds, and then it just disappears. The Editor never opens (I've waited 20+ minutes). This happens every time I try to open the project.

Additionally, when I try to open a project that's using 2019.4.2f1, I run into a similar but slightly different sequence of events. I see the splash image appear for a few seconds, and then Unity Hub automatically opens again. I've noticed that an error message appears when Unity Hub re-opens, but it disappears almost right away so I can never figure out what it says completely. Again, the Editor never shows up.

I've done some digging around, and I've seen other people run into similar problems. They've all suggested that I update my license. However, whenever I click the "Check For Updates" button I get a "Fail to write license file, please restart Hub and try again". This happens every time, even after multiple restarts. I've tried manual activation, but whenever I try to load the license file I just get a "Failed to load license file" message.

Some additional context: these issues started happening to me after a Windows update, after I downloaded Unity 2020.1.17, and after I updated Unity Hub to 2.4.2.

Any help would be greatly appreciated!

 

...of course, I ended up resolving this issue not too long after making the post!

Here was my solution:

I literally opened the Unity 2018.2.11f1 shortcut I have saved on my desktop. This then brought up a license error. I was able to enter my serial key, and get my license synced up correctly. Afterwards, I was able to select the project I wanted and it opened up successfully.

Now, opening a project that uses 2018.2.11f1 through Unity Hub works fine! I was also able to successfully open a project that used 2019.4.2f1 via Unity Hub as well, so I'm assuming any version will work fine now.

So, it ended up being a license issue. Definitely kind of weird, but happy I was able to fix this. Hopefully this helps anyone else running into similar problems.