Outlook Mac Slow or Freezing in Catalina or BigSur Posted on February 16, 2021 by timdotexe Terminal: defaults write com.microsoft.Outlook DisablePreviewForSMIME 1 killall cfprefsd Share this:Share Click to share on X (Opens in new window) X Click to share on Facebook (Opens in new window) Facebook Click to email a link to a friend (Opens in new window) Email Click to print (Opens in new window) Print