I think it's because OTR negotiates the encryption key for each chat session. This is part of the OTR idea/protocol. If you go offline with your OTR client the session key gets invalid, because the other side cannot know which client you're going to use next. If it's the same client as before I would be theoretically able to decrypt the offline messages, since this client could know the last negotiated session key. But if you use another IM client (maybe on another computer) you're not able to decrypt the offline messages as long as you don't transfer the last session key to this client. BTW, I think the clients deletes the session keys after a session for security reasons. Some OTR compatible IM clients are even so dump that they think the chat session gets closed when the user closes the chat window. With those clients it's even hard to get an encrypted session working when both users are online. In the beginning I was very excited by OTR, but after some weeks of fighting w
ith those teething problems I finally deactivated it and went back to the old crypto plugin. But maybe you don't have those problems with other clients. As long as you are satisfied with OTR you should not change it.

Regards,
Stefan

Dexter Filmore schrieb:
> Yes, I notced that, too and it's a bit annoying, given. But otherwise it works 
> so well and is so easy to setup that I still recommend it.
> Any idea why it can't store offline messages?
> 
> 
> Am Sonntag, 15. November 2009 23:27:19 schrieb Stefan Endrullis:
>> Your right, OTR has some advantages over the GPG plugin, but it has also a
>> major disadvantage. You cannot send encrypted offline messages. At least
>> not with the OTR plugin of kopete 0.12. Therefore I still prefer the normal
>> crypto plugin.
>>
>> Regards,
>> Stefan
>>
>> Dexter Filmore wrote:
>>> Just since the topic came up: I use the OTR plugin and found that to be
>>> rather good, it's cross platform, available for kopete, pidgin, trillian
>>> pro and others.
> 
> 
>