Created attachment 1283 [details] gdb trace 1. compose and send mail 2. switch to offline mode while sending ** (claws-mail:2221): WARNING **: [23:35:49] IMAP4-Verbindung unterbrochen (claws-mail:2221): Claws-Mail-WARNING **: can't append message /home/kardan/.claws-mail/tmp/queue.0x9e2050071392297 (claws-mail:2221): Claws-Mail-WARNING **: can't queue the message Program received signal SIGSEGV, Segmentation fault. 0xb6dd17d9 in _int_malloc (av=av@entry=0xb6f06440 <main_arena>, bytes=bytes@entry=2560) at malloc.c:3621
That's bug 2769 (also https://bugzilla.redhat.com/569478 ) but some other forms of losing networking (not clicking the "offline mode" button) can also crash Claws Mail when using IMAP.
*** This bug has been marked as a duplicate of bug 2769 ***