When opening IM, the viewer crashes completely without any message

and when nothing doing

Second Life Develop 26.4.0.33711709707

and on

Second Life Release 26.4.0.33661928315

New: After I cleared the cache, it started working again. But that's not really a permanent solution.

New: The viewer crashes when I have a profile open and then try to message someone who isn't on my friends list—but this doesn't happen with everyone I try to message. same is when a person want wrote me an im i crash

newest information: OK, it looks like there were too many old chat logs saved, and that caused some kind of chat log error. I'll keep an eye on this and see if I can find the specific chat log that might be causing the problem.