I'm sorry if this question has already been asked before:
I downloaded Krita v. 3.3.1 as an update, and noticed that I was having issues with saving files, even though I did not have those issues before with an earlier version. Usually, when I try to save something for the first time, I get an error message saying it can't be saved, or if not for the first time, the document isn't actually saved (it opens up a version from before it was saved). I've been trying to get around this by saving things as .psd files, but doing this I realized I can't save animations. Is this an issue with the way I have my computer/the program set up?

This should really be addressed. I literally have a fresh install and the thing crashes when I click save, save as, doesn't matter. I can save nothing.

How the heck _could_ we "really address this" if there is no useful information _at all_. What operating system are you using? Which file formats? What else, especially "security software" have you got installed? Where did you get Krita from? Why do you think that this is something that happens to everyone instead of your own systems? Give _details_. Of course, obviously, self-evidently, this behaviour is not how we sent out Krita into the world, so your assumption should be: "It must work for almost everyone. It doesn't for me. Something about my system is weird. Let me provide details about my system."

Provide those details, and we might get somewhere.

Alright. I really have no idea how these kind of things work so I wasn't sure what kind of information to include.
I have a 64-bit Windows 10 computer. I'm not sure what you mean by what kind of file formats. I've been having issues with .kra files not saving, and occasionally .psd files not saving. And you're right, I do have a software called OBS Studio used for recording. I think I first had that issue when I ran OBS without turning off Krita's OpenGL, which is something I was not supposed to do. There is another art program called OpenToonz that I have, though I doubt that that's causing issues with it, but it did download (I think) with a program that seems to be known for downloading with other software (an unwanted one) called ByteFence that's supposed to be an anti-virus software.
I'm not sure if that could help.

Antivirus software is known to cause problems when saving: it often blocks applications. Get rid of any "security software" that didn't come with Windows.

Alright. I got rid of it, and it works nicely now. Thank you!