Emails on one account show up late

Quit Mail. Force quit if necessary.

Back up all data. That means you know you can restore the Mail database, no matter what happens.

Triple-click anywhere in the line below on this page to select it:

~/Library/Mail/V2/MailData

Copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder

from the menu bar. Paste into the box that opens by pressing command-V, then press return.

A folder window will open. Inside it there should be files with names as follows:

Envelope Index

ExternalUpdates.storedata

Move those files to the Desktop, leaving the window open. Other files in the folder may have longer names that begin as above. Move those files, if any, to the Trash.

Relaunch Mail. It should prompt you to re-import your messages. You may get a warning that the index is damaged and that Mail has to quit. Click OK. Typically, the process takes a few minutes, but it may take hours if you have gigantic mailboxes. In that case, you may be able to speed things up by temporarily adding your home folder to the Privacy list in the Spotlight preference pane. Remove it when Mail has finished importing.

Test. If Mail now works as expected, you can delete the files you moved to the Desktop. Otherwise, post your results.

Please follow these directions to delete the Mail "sandbox" folders. In OS X 10.9 there are two sandboxes, while in 10.8 there is only one. If you're running a version older than 10.8, this comment isn't applicable.

Back up all data.

Triple-click anywhere in the line below on this page to select it:

~/Library/Containers/com.apple.mail

Right-click or control-click the highlighted line and select

Services ▹ Reveal

from the contextual menu.* A Finder window should open with a folder named "com.apple.mail" selected. If it does, move the selected folder—not just its contents—to the Desktop. Leave the Finder window open for now.

Log out and log back in. Launch Mail and test. If the problem is resolved, you may have to recreate some of your Mail settings. You can then delete the folder you moved and close the Finder window.

This action will delete any custom Mail stationery that you have created. If you want to preserve it, ask for instructions.

If you still have the problem, quit Mail again and put the folder back where it was, overwriting the one that may have been created in its place. Repeat with this line:

~/Library/Containers/com.apple.MailServiceAgent

Caution: If you change any of the contents of the sandbox, but leave the folder itself in place, Mail may crash or not launch at all. Deleting the whole sandbox will cause it to be rebuilt automatically.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.