Sometimes the data file for a mailbox can get partially corrupt. Common examples are clicking on an email then only to show a blank screen
Problem
- Message body appears in preview but when opened, body is blank.
Solution
1. Select your Inbox
2. Click Mail->Mailbox->Rebuild.
3. The view will appear to go blank.
4. This forces Apple Mail to reindex and recache the entire folder. Depending on the size of your mailbox this may take anywhere from a minute or two up to a few hours.
Important Notes.
- Remember that after you click "Rebuild", the view will appear to go blank.
- To fix the blank view, select another folder like "Sent", and then reselect Inbox.