Created attachment 103470 [details] backtrace of kmail threads after Quitting Selecting Quit from the file menu closes the main window and system tray icon but the kmail process does not exit. I've attached a text file which might help. After hitting Quit and waiting a minute, I launched gdb and attached to the kmail process. The file contains the backtrace for the active threads, which all appear to be in poll() or pthread_cond_wait(). I'm using kmail on Kubuntu 16.10, package version 4:16.04.3-0ubuntu2, on amd64, but the bug has been happening for a while (I think since upgrading to 16.10). It's 100% repeatable so I can help investigate if given instructions. There is no message on stdout or stderr when I hit quit. If I kill the process manually there is no terminal output, and I can start the program again as normal.
it was fixed long time ago in 5.3.x Regards