Several Hawk Wings readers have asked if the very successful trick of speeding up Mail.app by “vacuuming” the Envelope Index still works in Leopard.

I figured that there was only one way to find out.

I have no knowledge at all of SQL or the technical aspects of the management of data in relational database systems, and my post should be read in that light. However, I also have no fear, because I have backups.

So, as a lack of fear naturally produces recklessness, I decided to use the biggest weapon in the arsenal first. I quit Mail, made a copy of the Envelope Index file in my ~/Library/Mail folder by dragging it to the Desktop. Then I deleted the original in my Mail folder and started up Mail again.

It imported all the messages (with several heart-stopping pauses) and things looked good. The Envelope Index file was reduced from 37.4MB to 24.8MB.

However, doing it this way had two unpleasant side-effects, one of which I expected and one not. Mail then wants to re-cache all your IMAP messages and attachments. Even with ADSL2+ this takes a long time.

Secondly, the rebuilding somehow “broke” the syncing of to-dos between Mail and iCal. Mail told me that they were out of sync and asked if I preferred the list from Mail.app or from iCal. With iCal syncing in its current unworkable state, this lead to many opportunities for contemplating the spinning rainbow-coloured mandala of karmic retribution.

But eventually all was well, and Mail did feel faster. Then I tried with the Terminal commands. This was faster and resulted in a further small reduction. But it broke the to-do syncing as well.

Rumours suggest that the 10.5.1 update has already been released to developers for testing, and that it will fix many of the things which currently afflict users of minor, peripheral apps like Mail and iCal, including the stability of syncing. Perhaps it would be smart to wait until 10.5.1 is out and then try this.

In the meantime, I hope that someone smarter than me will tell me why this breaks the syncing of to-dos. Just for curiosity’s sake.