Version: 1.13.5 (using KDE 4.5.0) OS: Linux I use POP3 accounts on several mail servers. At least one of them is not very reliable and relatively often has problems to access. When this happens, KMail shows "Checking for new mail on ..." with 0% progress and CPU jumps to 99%; in top list it is kmail process that consumes CPU. Stopping check for new mail using "Abort Current Operation" immediately brings CPU consumption back to normal. Another case is resume from suspend. If system is suspended for a long time, POP3 session is dropped by server, so kio_pop3 simply hangs there. In previous (KDE) versions it just resulted in KMail missing new mails until kio_pop3 processes were killed. Now it triggers the same CPU hogging. Reproducible: Sometimes Steps to Reproduce: Hard to do on purpose; needs to provoke network failure to access mail server.
I confirm the issue: with a remote POP3 server being down KMail eats almost 100% of one CPU core at checking mail box. It takes 20 seconds. Then I see notification about failed access to mail server, CPU consumption returns to almost zero. KMail: 1.13.5, KDE: 4.5.1 (Kubuntu Maverick testing with enabled backports).
I confirm the issue on kde 4.6 (kubuntu 10.10) but no timeout, no notification, i must stop the task using "Abort Current Operation".
Confirming 4.6 (Under Kibuntu 10.10) is affected by the issue also. I think, it isn't a surprise as far as in Kubuntu KMail is still old KMail rather KMail2. Probably KDE developers are busy with polishing KMail2 making old KMail issues obsolete :-)
Thank you for taking the time to file a bug report. KMail2 was released in 2011, and the entire code base went through significant changes. We are currently in the process of porting to Qt5 and KF5. It is unlikely that these bugs are still valid in KMail2. We welcome you to try out KMail 2 with the KDE 4.14 release and give your feedback.