Trouble starting apps

I've been having trouble starting apps the last couple of weeks and need some advice on why this is and how to fix it.

For example, Thunderbird is almost impossible to get started and no technique works consistently. Sometimes it finally launches if I click the icon a bunch of times very quickly, sometimes even that doesn't work. The last time I tried it, I got a tiny frame fairly quickly containing only the Thunderbird icon, a minimize, maximize and close button and nothing else and no matter how long I waited, it wouldn't proceed beyond that. I couldn't enlarge it with the arrow keys and the maximize button was greyed out. I had trouble getting Edge to open too.

I really NEED Thunderbird to work since I use it a lot during the day so I'm hoping someone can help.

Windows Version: 2004.

dalchina said:

Unfortunately, despite the forum prompt, you've not specified your full Windows build. Win key + r, winver.

Therefore my answer may be irrelevant.

Have a look at all that was fixed - including erratic program starting- in this update:
KB4571744 Cumulative Update Windows 10 v2004 build 19041.488 - Sept. 3

Do you have that?

The prompt asked for Windows version so I thought that's all you needed; maybe you need to change the prompt to say version + build number?

Anyway, I have build 19041.508 so that includes KB4571744 automatically, right? (I don't see it in my list of recent updates but maybe it is implicitly part of the build?) If it isn't installed, how do I find it to download it?