I was really hoping it would be a simple restart!
You said you did file checking, was it like this?
I’m trying to reproduce the issue on my end but that part of the tutorial (It’s a really good tutorial!) goes perfectly fine for me when I do it, using 5.4.4.
If you did the verify, you can also try uninstallation/reinstallation. Other than that I’m not really sure what to do but I’ll keep looking!