I tried that at one point, and it worked great until MY charm effect wore off. At that point, my PC (the one who was charmed) turned hostile, and he wouldn't unhostile. I eventually had to reload to fix it. Cast Animate Dead, and have those walk up to the sirines while a scout keeps watch from a distance. The skeletons are immune to charm, and a pack of them can actually kill off some of the sirines by themselves. This works especially well if there are several sirines in a cluster, since they'll all blow their charm abilities on the skeletons.

Ah true, I didn't remember that, your caster level seem to b e minor to those of the sirens, therefore your spell dispel first. I had the same issue, so, basically I killed quickly the sirens, charming the charmed, and then fleeing from the charmed's one!

I don't think that was the issue. My problem is that when my charm wore off, my guy flipped from non-hostile back to hostile (the Sirine charm had already worn off).

Actually, maybe that is what caused my problem: my PC was hostile before I charmed him, so he was reset to hostile when my charm ended?

Maybe was a unique case (bug) ?

Is true that the charm effect from the sirens remains A LONG TIME measurement in minutes (I think was modified for BG2 by the devs).

The last charm effect remains, that is, if you charmed a PC will be useless, but if you charm a charmed (the cham-cham!) then is useful ( I think its even in the toolstip) until tthe last charm effect expired, then the previous one remains in effect.

Looking elsewhere on the web, BG 1 doesn't auto-hostile the target when the charm expires, so I guess that wasn't it after all.

Maybe it is as you say, that I just didn't wait long enough for the sirine charm to expire. It was odd though, because I had time to mostly clear the golem cave with one of the books when suddenly my PC went hostile. Dispel Magic failed to fix it, couldn't rest because of hostility so I couldn't try other spells, just an icky situation.

Anyway, a skeleton pack prevented any similar issues from cropping up with the other sirines on the map. :)

Here is something you could try, provided the charmed character is not the main character.

1. Try killing the character, and then reviving that character. (Note that Raise Dead has no long term penalties to the revived character in this game.)

If that doesn't work:

2, Try charming the character, and then kill the character while charmed. Then, revive that character.

Death is actually a cure for pretty much anything in these games. In BG2, it can even cure level drain; kill and revive a character and all lost levels will be restored, no need to cast a spell that causes fatigue.

It's worth noting that, if the character has cast Polymorph Self, death will end the effect, but not take away the shapeshifting abilities the spell grants. This is an obvious exploit that gives you permanent Polymorph Self capabilities. If this happens by accident, you can remove the abilities by casting Polymorph Self again and letting it wear off as normal.

There may be other oddities as well. (I heard something might happen with BG2's sequencers possibly becoming forever unusable, though a patch might have fixed that.)

My PC is a Dwarf Fighter, with the biggest armor and shield I have available. Usually he stands up front while everyone else fills the target(s) full of ammo.

Therefore, it was poor CHARNAME that fell victim to this. I think I did eventually try killing him, just to see what happens, and I got the expected game over.

One other thing you could try: Enable cheats and cheat keys, then do Ctrl+R on the charmed character. See if that fixes it.

I ended up reverting to a previous save, I'm far past that part, and I've long since overwritten the saves from that time period. Someone brought up counter-charming to readjust a party member's killing priorities, so I related my tale about counter-charming (and my sirine charm solution).

I opened a thread about it at the time, but none of the solutions suggested before I reverted worked. Granted, I didn't wait long, since I was busy playing.

One thing I found out while I did my play through in BG1 Vanilla is that the dispel magic spell actually removes the sirenes charm effect on the character, just have the mage hang back with this spell and focus on the sirenes, when the mobs are down, or too many PCs are charmed, hit them with the spell.

Yeah, dispel magic is fun in bg1 with its 100% success rate. I wish it would stay that way, but might be too overpowered in bg2.