I found out what the problem was. I had set the preferences to compact folders after deleting 24000 bytes. When I increased this to 2400000 bytes, the behaviour stopped and emails clear again in a flash when I delete them from my inbox.

I use Pegasus v4.41 on Windows XP pro.

When I delete emails from my inbox to my "deleted messages" folder, winpm-32.exe takes 99% of my cpu to make this happen. Moving emails from my inbox to any other tray is not a problem and doesn't result in heavy cpu action, but moving emails from my inbox to my deleted messages folder takes way too long. Deleting several emails (say between 5-10 regular emails, text messages without attachments) at once can result in being bogged down for 8-10 minutes at a time; obviously with that amount of cpu usage I can't do much else while waiting for the messages to clear so I only remove my emails now when I know I'll be away for 15 minutes at least.

This started happening when I exchanged Norton AV for NOD32, but it's not NOD that's taking up the cpu. Does anyone have any suggestions? I have also posted this at the NOD 32 forums but NOD32 is barely changing activity, whether cpu, VM or Mem Usage. If I receive a reply there, I will report it in this thread if it is relevant.
 

Thank you in advance for any suggestions.