MBM editing very slow / beachballing / freezing

[pwdrnow]

MBM v8.4.2 - MacBook Pro Retina 15" 2.8/768 SSD/16GB RAM

I've been having lots of trouble lately with MBM refusing to edit text at times, and other times beachballing for a few minutes before releasing the app again to edit... then it happens on every subsequent edit. Other times beahcballs forever until I force quit MBM.
Happens when opening existing files (which I normally do to create next mailing) but seems to not happen so much when creating new files (which I do very seldom).

Have tried perms repair, restart, relaunch MBM, Zap PRAM.

Any help much appreciated.
Thanks

 

[stanbusk]

I use MaxBulk Mailer in a similar computer but 13", also retina, I have no problems at all. I guess you have tried to restart your computer right?