Thunderbird might hit a hiccup like:

• One of the accounts/folders isn’t synced fast enough on startup
• Something in the search breaks and Thunderbird silently drops it
• The “Favorites” flag might actually make it more likely to vanish (yep, counterintuitive)

Step 1: take a screenshot or note the search terms. That way if it goes poof again, you’re not rebuilding from scratch.

Step 2: Recreate the Saved Search without marking it as a Favorite This sounds dumb, but it’s helped others, for some reason. If being a Favorite can make it more likely to vanish,let's try not doing that and see what happens.

Please describe WHEN the saved search disappears, and also check Error Console (cmd+shift+J).

FWIW, I have two saved searches marked as favorite for about a year, and never have a problem. Both reference more than one account - one is fast mail and the other is google based.

Thank You very much for your replies. I've been watching it through the week and it's playing a Houdini act -- it keeps disappearing and reappearing, in the home account and Favorite Folders. It's been stable for the last 24 hours, so I'm going to leave it alone for now. Again, Thanks for your responses.

John