File Explorer Inaccessible (as of the recent May 2019 update)

Literally the very moment it goes to access the File Explorer is when it stops me. The only exception is when I go to upload a custom Gamerpic. There, it gives me a loading icon first like it's going to let me through, then I'm hit with the same error prompt
after a few seconds, so I still never get to a point where I'm browsing anything within it.

But as mentioned in the OP, I can open up things from within the File Explorer itself just fine, such as for the purpose of changing the dashboard background, opening up video files, text documents, etc. And certain programs, a music player in this case,
that make use of a USB can also do so, such as the app called 'Simple Background Music Player'. That reads MP3 files stored in a specially named folder in the attached USB, though it never directly opens the File Explorer.

Pretty much so long as it doesn't bypass the need to enter it and select something, e.g. a file to export or something being downloaded into it, I get an error prompt. No associated code or anything, just a screen that suggests their service isn't working
right and to check the status page, which has all green checkmarks most of the time I've checked. And if there wasn't, it was a game of some sort having issues.

Also many things are running a lot slower and my cookies no longer seem to be getting saved. Have to log in again everywhere if I restart Edge.

It could just be an issue on there side from the way you explained it. try checking on that for now

Can I ask, when you try to open or save a file, how far do you get before the error message shows up? Does it show up almost immediately before your able to pick a location? Or are you able to browse around and select something, only to have it crash soon
as you hit "Save" or "Open"?

Still having the problem. Status page still says everything's hunky-dory.