As more or less the same issues are present in OS 10.9, you'll find a comparable trick there: http://duckrowing.com/2013/11/29/fixing-smart-folders-in-os-x-10-9-mail/
Unfortunately, it didn't work for me and I couldn't get smart folders back to work yet... :-( I'm still investigating.
Used speedmail on Mail 4.6 on MAC OS 10.6.8. Rsult: I lost all the bodytext of my older emails. Only the titles appear. Are the messages themselves archived somewhere else on my computer? What do I do to make them appear again?
In fact, we have some problem with some of our utility and Lion. We have
planning to release a fix for them soon. Exept for our last product,
Lucien, that's born exatly for Lion :)
Take a look
You will see that all our others utilities will be ready in MacUpdate page
Before app bashing this simple little tool, please remember us mortal Mac users. SpeedMail is written for people like me and I am very grateful that there are developers out there who understand that there are Mac users who never open Terminal, let alone type in it.
The app is identical to VacuumMail ( http://www.macupdate.com/info.php/id/24410/vacuummail )
You can also open Terminal and type:
sqlite3 ~/Library/Mail/Envelope\ Index vacuum;
SpeedMail and VacuumMail are wrappers for simple, one-line terminal commands. Nothing more.
I was a bit wary, but because I had just done a full mail back up...i tried it. Very noticeable speed improvement! Always wondered why there wasn't any optimizing app for all the data files Mail.app manages. GREAT JOB. Keep It Up!
Speeding up Mail sounds great. But I won't install or run this, until I know what it actually does. I don't want to lose my database... Please add that missing information, and I'll give it a try. Thanks.