Why has moving emails from my inbox in Mail.app become so slow? Sometime in the last few weeks, Mail.app has become painfully slow when moving an email out of the inbox and into a folder. I have five email accounts that I check in Mail.app—one is pop3 and the other four are IMAP (gmail or google apps).

Moving an email from the pop3 inbox to a local folder still works fine. However, when I drag/move an email from the inbox of an IMAP account to a folder, the email in the inbox turns gray and stays there for 2-4 seconds. This used to not be the case. In the past, even though the move might take time to replicate on the server, in the inbox of Mail.app the email would immediately be removed.

I've captured a screenshot of the behavior showing the grayed out emails.



Did something change in the last Software Update? I installed the OS X 10.6.6 update on 6-Jan-11, so that could account for when this problem started.

I'm running Mail.app ver 4.4 (1082) on OS X 10.6.6.
Under the View menu, check Hide Deleted Messages. That way, messages marked for deletion are no longer shown, and will be processed the next sync (like they used too).

It is possible you activated it unintentionally (it's just a ⌘+L away on the keyboard).