Minecraft – Resetting the End on Xbox Minecraft

Popular modern filesystems will not go out of their way to actually overwrite the data on the disk or securely delete it when overwriting a file. It is therefore theoretically possible to restore the overwritten file if the stars are right (no blocks were overwritten since the file was deleted/overwritten). However, there aren't any utilities that run on an Xbox that could do this, and hooking up an Xbox HDD to a PC and finding software that will work with its proprietary FS may be more (legal) trouble than it is worth.

Sometimes it is best to cut your losses and move on.

It's possible but unlikely. End Portals do spawn in strongholds in the console version of Minecraft, so it's not an issue of version. It's possible, however, that the portal was overwritten by something else in world generation (a dungeon in precisely the same place, or a mineshaft running through your stronghold).

What is more likely, though, is you haven't searched the entire thing. Strongholds are quite extensive, so it can take a long time to go through the whole thing (speaking from experience, I have made bases in strongholds a few times. They can be huge).

Unfortunately, since you are on the console version, ender eyes only point you to the stronghold itself, not the portal, so the only real advice I can give you is to keep looking, and clearly mark where you have been. I like to put torches on the right-hand side of corridors as I move through them, so I know if I am backtracking or not.