A poster on the Apple Discussion Boards is having a very weird experience with attachments in his IMAP account.

Dylan Muir finds that when he views large attachments stored on his IMAP server in Mail.app, they are corrupted. If he views them in a webmail client, they aren’t. If he views them in Thunderbird, they aren’t. It’s only Mail.app.

Unusually, the Apple Mail gods on the Discussion Boards seem to be out of ideas.

I wonder if anyone here has experienced this too (I never have), and knows what’s going on.

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Envelope Index (see “What’s in your Mail folder?”) is an SQLite database that stores key information about your emails. Over time it can get terminally corrupted (see “The dreaded ‘your home directory is full’ message”).

It can also suffer a large number of smaller hiccups and corruptions which slow Mail down, although they don’t knock it out.

A poster on macOSXHints explains how his database stored phantom messages from an Exchange server he used over Summer.

Quitting Mail, dragging the Envelope Index to the Desktop, restarting Mail and allowing it to reindex his emails, cut its size from 200MB to 2MB. The speed increase was significant. Rob Griffiths reduced his from 25.9MB to 4.5MB.

My result was less dramatic (21.6MB -> 17.6MB) but Mail.app still feels a little more zippy.

Worth a shot for you too, perhaps? If so, first make sure you have a backup of your ~/Library/Mail folder in case something goes wrong. Dragging it out of Finder onto your Desktop will do the trick.

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