I'm hitting this assert pretty regularly recently.
Created attachment 107500 [details] backtrace
this isn't happening anymore
Git commit 149f88ea2f7beadaff24d03f59d02cedf0176f98 by Daniel Vrátil. Committed on 04/09/2017 at 19:25. Pushed by dvratil into branch 'Applications/17.08'. IMAP: handle when RetrieveItemTask fails to find the message Can happen if the Akonadi database contains invalid items or when the Item is deleted before the task is dispatched. FIXED-IN: 5.6.2 M +5 -1 resources/imap/retrieveitemtask.cpp https://commits.kde.org/kdepim-runtime/149f88ea2f7beadaff24d03f59d02cedf0176f98