Comment 4 for bug 410723

Here is also a workaround in Evolution FAQ:
http://www.go-evolution.org/FAQ#Why_do_I_get_an_error_.22Summary_and_folder_mismatch.2C_even_after_a_sync.22.3F

 Why do I get an error "Summary and folder mismatch, even after a sync"?

If you get an error pop up like: "Error while Expunging folder. Error storing `~/.evolution/mail/local/Inbox (mbox)': Summary and folder mismatch, even after a sync.". Try the following operations:

    * Stop evolution completely with the command "evolution --force-shutdown"
    * Remove the corresponding files with the file ending ".ev-summary" and ".ibex.index", in this example you should remove the file "~/.evolution/mail/local/Inbox.ev-summary" and "~/.evolution/mail/local/Inbox.ibex.index".
    * Restart evolution, it will be slow to come up because it recreates the indexes.

For your interest, this is filed as https://bugzilla.gnome.org/show_bug.cgi?id=550414.

As a side effect of removing the summary, you will lose locally stored mail labels.