7.13.10 How can I rebuild Apple Mail’s database?

Many common problems with Mail can be fixed by rebuilding all or part of its index database. For example:

You have a mailbox that shows a number of unread messages in the mailbox list, but when you click on the mailbox there do not seem to be any unread messages inside.
Messages seem to have disappeared; they show up when you search your Mac using Spotlight but not when browsing or searching in Mail.
A smart mailbox doesn’t seem to be finding the messages that you think it should.
You click on a mailbox that you know contains some messages, but Mail doesn’t show any.
Messages are colored as spam but remain in the inbox, even though your SpamSieve rule is set to move them to the Spam mailbox.
You try to delete messages, but they come back or Mail reports an error.
Mail is very slow at browsing or searching messages.

To do a complete rebuild of Mail’s database:

Quit Mail.
Locate the Envelope Index file. On macOS 14 and macOS 13, the file is stored at:
```
/Users/<username>/Library/Mail/V10/MailData/Envelope Index
```
Open your user Library folder. (See the How can I open the Library folder? section if necessary.) Then open the Mail folder, then V10, then MailData to find the Envelope Index file.
- On macOS 12, the MailData folder is inside of the V9 folder rather than V10.
- On macOS 11, the MailData folder is inside of the V8 folder rather than V10.
- On macOS 10.15, the MailData folder is inside of the V7 folder rather than V10.
- On macOS 10.14, the MailData folder is inside of the V6 folder rather than V10.
- On macOS 10.13, the MailData folder is inside of the V5 folder rather than V10.
- On macOS 10.12, the MailData folder is inside of the V4 folder rather than V10.
- On macOS 10.11, the MailData folder is inside of the V3 folder rather than V10.
- On macOS 10.7 through 10.10, the MailData folder is inside of the V2 folder rather than V10.
Once you’ve found the Envelope Index file, drag it to the trash. Also delete Envelope Index-shm and Envelope Index-wal (if they exist).

Note: Rebuilding the index database is normally perfectly safe. Even though it seems that you are deleting a file, Mail stores its primary copy of your message data elsewhere. When you delete the damaged database, Mail uses this primary copy to create a new index database. However, please be careful if you are using macOS 10.15. We’ve heard some reports that rebuilding the Envelope Index can lose messages in On My Mac mailboxes on macOS 10.15.0–10.15.2 due to a bug in Mail. If you are using macOS 10.15 prior to macOS 10.15.3, be sure that you have a backup first, and proceed with caution.
Relaunch Mail. It will welcome you as if you haven’t used it before. This step may take a few minutes, as Mail searches through all of your stored messages to build your new database file. IMAP and Exchange messages will need to be re-downloaded from the server.