Is there any way to switch between the My games and apps and MS Store tile at the bottom...

Just to elaborate on the 'shutting down apps' discussion, some apps stay open until you quit them and you can have several open at a time without really realizing it. The nice part is that your most recently used apps show up on your home screen. The last
(or current) app in use shows up in the large tile and the other recently used apps appear around the large tile. Just scroll around and highlight any of the apps, hit the menu button and if the app is still running, the option to quit will be listed.

I will typically go through and do a quick check / shut down of all the apps on my home screen before I start to play a game. Not that any running apps will bog down your games, they're handled by a different OS, but if you do a lot of switching between
apps or your FL, game DVR, etc. while gaming, not having a bunch of unnecessary apps running will help make the switching between game and app run faster and smoother... at least that's been my experience.

Oh and congrats on getting your X1.

One instance is most likely on the bottom right as that is the tile that shows what's in the disc tray. The other tiles at the bottom show your most recently used games or apps, hence one of those tiles also shows the game you have just stopped playing.

The Windows 10 update-in-place did not resolve the Xbox PC app issue. I uninstalled anything that said "Xbox" in front of it prior to running the update-in-place. It took about 25 minutes so not much time lost, and everything seems to be working fine as it did prior to the update-in-place. I then reinstalled the Xbox app from the MS Store which went fine, but no dice on the Xbox app. Same garbage "could not load content" tiles showing up in the app, and my Xbox game pass subscription does not load within the app. Even when I completely sign out of the Xbox app, those same garbage blank graphic tiles load when launching the Xbox app for PC.

Not sure where to go from here, but definitely not willing to do a format/reinstall just to get the Xbox and MS Store app working. I can only assume at this point that there's an issue going on with auth/tokens/account provisioning/etc. between that PC and Microsoft.

Check the Windows Store tile for any app updates.

I uninstalled from within the tiles screen (right-click on the Minesweeper tile and choose uninstall from the menu on the bottom). Then I shut down, and restarted after a few minutes. Then I reinstalled from the app store. Although the game does start in
instruction mode, I still had all my points and goodies. More, in fact, as the game started with 7 lives (and seemed to be rewarding me with an abundance of maps and dynamite). Still, a true fix will be welcome.