How do you identify the affected message referred to in #3?
MacBook Pro, macOS Sierra (10.12.4)
Do you remember what message was selected when it crashed? If so, select it and see if it crashes. If it doesn't, arrow through each message until you find the one that causes the crash.
Sorry, I thought this was part of the thread started at https://support.apple.com/en-us/HT203542
Mail may quit when you view an email message that is malformed or damaged, and it may continue to quit as long as the message remains selected. Resolve the issue by following these steps to delete the message:
1) Open Mail and immediately hold the Shift key until Mail opens. This causes Mail to open without any message or mailbox selected.
2) Hide the message viewer portion of the window by carefully dragging the thin separator bar between it and your list of messages. Keep dragging until Mail shows only the list of messages, not the message viewer. In this view, you can see messages only by double-clicking to open the message.
3) Click the affected message once to select it without opening it. Then press Delete or choose Message > Move to > Trash.
Try rebuilding the mailbox.
If that doesn't work, try re-indexing the mailboxes. This can take awhile if you have a lot of mail.
Reindex messages For El Capitan, try looking in V3. Sierra use V4. High Sierra use V5.
Reindex messages (2) See post by Linc Davis
If that doesn't work, try Mail/Mailbox/Export Mailbox to save your emails. Then start deleting emails, quit and reopen Mail and test until you find the email causing the problem.
Please read Writing an effective Apple Support Communities question. We can't see what you see, and have no associative idea about what you are referring too. Is that waterhole #3? The third hole at St Andrews?
Sorry, I find no way to edit this post and I thought this was part of the thread started at https://support.apple.com/en-us/HT203542
Here is the thread:
Mail may quit when you view an email message that is malformed or damaged, and it may continue to quit as long as the message remains selected. Resolve the issue by following these steps to delete the message:
1) Open Mail and immediately hold the Shift key until Mail opens. This causes Mail to open without any message or mailbox selected.
2) Hide the message viewer portion of the window by carefully dragging the thin separator bar between it and your list of messages. Keep dragging until Mail shows only the list of messages, not the message viewer. In this view, you can see messages only by double-clicking to open the message.
3) Click the affected message once to select it without opening it. Then press Delete or choose Message > Move to > Trash.
VERY inconsistent. Sometimes I'll get the spinning ball immediately upon launch and within 30 seconds Mail will quit. Other times I can go for awhile without incident, then ... bam, the ball and a quit. I'm having to go online to the server to get anything done.
That doesn't sound like a problem with a particular message, but I don't know what would cause it.
Are all of your Mail accounts IMAP or other online storage such that you could delete all of the accounts and re-add them to Mail without losing your email?
Nope, nothing. I've clicked through a zillion emails and ... nothing!
Does it still crash when you open a message?
All accounts are IMAP. I may have to delete and re-establish accounts but I'm waiting on that move as a last resort.
Deleting the account and adding it back often resolves account problems. Have you been able to isolate the problem to any particular account?
No, so much of this process is trial and error. You just hope during the trial phase you don't mess something up that is not reversible lol.
How do you identify the affected message?
