Dmitry> Hi, On my system, 21.2.22/23 fails while sending Dmitry> base64-encoded data via smtp. Using smtpmail-debug-info, I Dmitry> see that it starts sending lines of base64 encoded data, Dmitry> but after about 100-150 lines (the exact number varies) Dmitry> process-send-string just hangs. C-g cancels it Dmitry> successfully but the message does not get sent of Dmitry> course. This could be somehow related to a fix I submitted long time ago: 1999-02-02 Gleb Arshinov <gleb(a)cs.stanford.edu&gt; * process-nt.c (nt_send_process): Fix for process-send-region/process-send-string breaking when size of the input > 128 chars: change maximum chunk size for process stream from 512 to 128, thus guaranteeing that ntpipe_shove_writer succeeds. Probably not, but how knows. Gleb