The Hoarfrost Castle mod adds a new room to the Cheydinal Mages Guild Basemant - [REFR:8B006F06] (places CheydinhalMGBasemantDoor01 "Wooden Door" [DOOR:0006DBC6] in GRUP Cell Temporary Children of CheydinhalMagesGuildBasemant "Cheydinhal Mages Guild Basemant" [CELL:00006917])
Ownership is set to Falcar "Falcar" [NPC_:0002CD21], but no lock.
The door does not lead to a new cell, just a new room in the same cell.
When i enter the basment the door is unlocked and there is no red to mark it as owned, but when I open it and enter the room it slams shut behind me and locks.

Any idea what is going on here? The door is not referenced by a script or anything else.

Only possibility is that another mod in your load order has edited the base door, attaching a script to it.

Heh, actually it's Oblivion.esm itself that adds this script to the base door:

ScriptName CheydinhalMGBasemantDoorScriptfloat timerBegin Gamemodeif ( GetStage MG02Alter < 30 )	if ( GetOpenState == 1 )		if ( timer < 6 )			set timer to ( timer + GetSecondsPassed )		else			set timer to 0			SetOpenState 0			Lock		endif	endifendifEnd

So I guess using that particular door type was an oversight on Hoarfrost's part. Oh well, I'll copy the door to my custom patch, lock it and make Falcar's key open it.
The hard core option would of course be to wait untill Falcar enter and then either steal or loot his key, but I hardly think that was intended to be.

Curious, that script wasn't attached to it in my copy of the Hoarfrost ESP. But then I might have edited that out a year or two ago and completely forgotten :shrugs:

Heh, you got it right in your previous post.
The script is attached to the base, vanilla door. I think the vanilla game only uses it for the door to Falcar's quarters, since the player character is not supposed to be there before finding the Ring of Burden. Of all my mods it's only Hoarfrost which also uses that particular door type since it adds a room in the basemant cell. But unlike the door to Falcar's quarter the Hoardrost door is not locked, and not marked with the red trespass sign.

And just a head's up, but the latest UOPS alters the packages of Deetsan and Trayvond so they will go downstairs to sleep I don't think this affects any of your issues or that mod, but just thought I'd mention it. They will sleep in one of the beds in the other bedroom, not Falcar's quarters.

Then I must have come across this myself a long time ago, and swapped the base door out for the non-scripted version, then completely forgotten about it. Probably I did this back when I created the compatibility patch for Hoarfrost and OMG.

I was unaware you ever made a patch for Hoarfrost and OMG.

Is it hosted anywhere?

Yes, you can find it http://www.tesnexus.com/downloads/file.php?id=29905.

Ahh the secret stash ... thanks

Oh my, this find of the patch for Hoarfrost Castle and OMG is just so helpful! Thanks a lot DisplayName for making this! :thumbsup: