Hi, all. After installing the third downloadable mod from Bethesda (Wizard's Tower), I've found that the Mystic Emporium is always locked, even during the day.
After experimenting for a bit, I discovered that the problem fixed itself (once Calindil re-evaluated his packages) if I removed a particular mod that had added spells to him.
So, presumably there's a conflict. The Wizard's Tower mod adds an extra person in the Mystic Emporium, and so they changed the locked door to the shop from being owned by just Calindil to being owned by a new MysticEmporiumFaction. However, if you have any mods that modify Calindil (such as directly giving him extra spells to sell), it overwrites the Wizard's Tower version of him and he's no longer a member of the new faction, and so fails to unlock the door.
There's actually a neat suggestion on the CS Wiki about how to add spells to vendors in a way that won't cause conflicts. I'm going to modify the mod that's conflicting (the Call Steed/Saddlebags mod) myself to add the spells to Calindil this way, and hopefully it'll fix my problem.
Just thought I'd share my findings.
Edit: That's the Mystic Emporium in the Market District of the Imperial City, BTW.