Error 0x87e00002 when tried to transfer a game from Series X Internal SSD to external HDD

Not really...

Xbox Series X games / upgrades / updates has to be installed onto the Series X internal or expansion card SSD,

You can have Xbox One games on your external hard drive that will get an Series X upgrade but the games will need to be transferred to the Series X and then the Series X upgrade will need to be downloaded onto the Series X SSD,

As an example...

I have Marvel Avengers on my external hard drive that will get the Series X upgrade and I will transfer the game over to the Series X SSD ready to download and update the game to the Series X version when available.

Series S. it seems to be any game. I haven’t found one I can play directly from the hard drive yet. In honesty I haven’t tried many but seemed odd that I haven’t found any yet?

The only games that would be directly playable from an HDD would be Xbox one games.

Xbox Series X/S games can only be stored but not played from an external HDD. Those can only be played from either the internal ssd or one of the WD or Seagate expansion ssd's that plug into the back.

The reason is the Xbox Series X/S games are setup to take advantage of the speed of the internal ssd. For comparison Internal SSD has raw read speeds of 2.4 GB/s whereas HDDs would only be a max of 500 MB/s.

I have the same question. I have FH4 and Gears 5 on external hdd and i play on Xone X. What will happen when I plug in my external hdd to my new x series x. WIll the new concol see games already installed on my external hdd and how then smart delivery
will work?? Must I change location of FH4 and Gears 5 from external hdd to internal ssd to use smart delivery?

You can still use external HDD for your Xbox/Xbox 360/Xbox One games but you can't play Series X/S games from them,

Series X/S games can only be played from the internal or external storage card,

with game file size's getting bigger, that 1Tb internal NVMe SSD is going fill up quick.

You can or should be able to use it for the Series X but i don't recommend running your games from it,

as you wont get the fast loading or fast travel time of what the Series X custom NVMe SSD is capable of,

It's best to use any external HDD or SSD for just game storage and transfer you most played games onto the Series X NVMe SSD.