I kind of suspected that Shadowmere may not be an unkillable unique character as she was in Oblivion, and a quick glance at this forum has shown that may indeed be the case. At any rate, I've always been pretty careful with her. I don't bring her too close to a place where there may be large amounts of combat. However, she seems to have vanished.

I was doing a quest for the Imperials, storming some fort. I dismounted a good distance from the fort and engaged on foot to ensure that she wouldn't get involved in the fighting. When all was said and done, I headed back to where I left her and hopped on without thinking. It was dark at the time. I fast traveled to a town, and as I dismounted again I realised that the text did not say "Shadowmere", it just said horse. I thought nothing of it, figured I'd just look around and see if she came with me when I fast travelled. No luck. She wasn't near the fort that I had left her at. Checked back at the Sanctuary and waited for a while, nothing. Apparently, she has just vanished and I don't think I'll be seeing her again.

Has anyone else had this happen? One would think that with her being a unique character/possession, she wouldn't just disappear like that.

Anyone?

Dunno, Don't have her yet, but I know in Oblivion she would return to her home when lost.

I figured she would, but like I said that hasn't been the case.

Hmm.. must be a bug then.

I had the same problem. After searching on the net I came across the cheat code of salvation: player.placeatme 0009CCD7
Shadowmere with spawn next to you in full health and ready to go.

Shadowmere's disappearance must be a bug so if you are a PC user just use this cheat until Bethesta releases a patch to fix the bugs, as i hope they will. =P

If u use XBox or PS3 the best solution I've found is to retrace your steps and maybe you'll find her where you left her. GL

I am also experiencing this problem. I can't find Shadowmere anywhere. Best quest reward ever, now it's just missing.

My Shadowmere died from a 10 foot fall that would have barely hurt me... I was so disappoint.