I enthusiastically used MailTags starting almost from the day I got my first Mac and until the last Friday. The reason I gave up was that my Mail.app has been choking on MailTags for the last several months. Working with email has become painfully slow: most of the time the bulk of the memory and over 100% of CPU was consumed by “Saving MailTags”. Rebuilding mailboxes and databases, re-installing and cleaning caches, and archiving old mail did not help. Finally I decided to remove MailTags by deleting ~/Library/Mail/Bundles/MailTags.mailbundle. I am now able to zip through my mail again. I am missing my keywords and projects a bit but the re-gained ability to search and jump between folders more than compensates for it. Brett Terpstra spoke about doing the same on this episode of MPU. He hopes MailTags will bounce back. Me too. Meanwhile, it’s one more lesson to make my filing and tagging system redundant and non-proprietary.