well illegal MUI stuff pops up all the time. Sometimes the inbox in nowhere to be found for a day or two. Locks up the OS 4 or 5 times a day. Look I could go on and on. It is a kindergarten 8 year still in beta, 101 baby email client and a poor attempt of a program, bug ridden mess. on a scale of 1 to 10 it is a 0 at the very, very VERY! best. I am very understanding that things are not so great with apps for AmigaOS4 and that is ok as long people are working to fix this. Trevor said at amiwest 2014 content, content and more content..
i'm sorry you've had that experience. simplemail works very well for me, and does not 'lock up' my system. i keep it running constantly, actually. perhaps if you had specific issues, you could bring them up with sebastian? i'm sure he'd appreciate bug reports to make it better.
-- eliyahu