Could not save [file path]/[file name].kra
Reason: Could not create the file for saving

At least that's the error message I get trying to save my current project. I've also tried to save it onto different hard drives and as different file formats but nothing works.
Using a Laptop with the latest version of Windows 10 and Krita 3.3.3 installed - and I really need to save this drawing for art class before the next OS crash.
I mean, I've used Krita a bunch of times now but never had any issues like that. So what am I doing wrong?

Wow, I'm such a genius: Having some special characters like |/ and so on in the filename will of course cause an error when saving.
But the real question is: Why does Krita neither prevent me doing this nor tell me why the error was dropped?

If you have native file dialog enabled, it is supposed to do it. It was changed to be enabled by default on 3.3.3, but if you had used a previous version it might be set to off. You can consider enabling it.