After getting Adalon's illusory Drow forms, I did the Illithid Lair and Beholder City quests. When I approached Ust Natha, the guard recognized me as Drow, but as soon as I passed through the gates, all the drow were hostile. I know I can bypass Ust Natha and exit the Underdark through the Kuo-Toa Dungeon, but I don't want to miss out on the experience and items to be gained in Ust Natha. How can I verify whether Adalon's spell is still in effect, and how can I regain it if it's somehow been lost?

Someone who knows the game better can probably answer this more accurately than me. I do remember someone having a similar issue from a while back, and I think that in that case it was caused by a bug. For now, if you have any earlier saves, don't delete or overwrite them! I realise I may be stating the obvious here, but better safe than sorry: in a worst case scenario you may have to go back to before the start of the chapter, or something, to correct it.

How did you address the gate guard when he challenged you? If you don't act like a Drow, ie. if you cow tow, or if you say you have come from the lair of Adalon, the city will immediately go hostile.

Regardless, you will have to load a save prior to the gate meeting if you want to explore Ust Natha, trade and such, since hostile status of NPCs is written to saved games, so even setting the global variable for the city not being hostile won't help if you've already entered it.

To gain access to Ust Natha, I claimed to be "Veldrin from Ched Nassad." Because my protagonist is female, I made disparaging reference to the guard's masculinity. The guard then recognized my party as Drow.

I have a saved game from before my approach to the Ust Natha gate, Perhaps I should mention that I did not encounter the scout which some people describe as running ahead to the gate.

Following up on a report of a similar problem, I tried using the console to set the Global Variable DROWCITYHOSTILE to zero, but as with that earlier report, the problem persisted. That problem was never solved.

Yes, once they are hostile, it is too late to set the variable DROWCITYHOSTILE to zero. Did you try setting that variable to zero just before entering the gate ?

If you did and it didn't work, can you upload somewhere your savegames ?

Possibly both the one just before entering and the one just after entering the city (just zip or rar the whole folder). I cannot guarantee I will find a solution, but I could take a look with tools like NearInfinity to see if I can find something useful.

And when the gate guard said that you may pass, did you go straight into the city? At the point where the gate guard lets you pass, you have no more than 3 in-game days to visit Solaufein, otherwise your cover is blown.

As I said before, setting that variable will not help once you've entered the city and people are already hostile. Don't bother even trying.

Getting the illusion from Adalon and postponing entering the city, ie. by going to the Kuo Toa and Illithid cities is not an issue. Adalon's disguise will last as long as it needs to last, and as long as you don't betray her.

My apologies. In copying the console command, I somehow omitted the second parameter. When it's included, it solved the problem. For the benefit of anyone who may encounter this problem in the future, here is the correct command:

CLUAConsole:SetGlobal("DROWCITYHOSTILE","GLOBAL","0")

Hickory deserves credit for this solution.

My appreciation also to Ergos for his willingness to research this problem further had it proved necessary.

Thanks for posting the proper fix. Many people don't follow up once they fix their game, often leaving others flailing about wondering how it was fixed. You should mark his post as the solution, then. :)