Mail crashes when I open a specific message
Try this, it helped to me, but mail didn't crashed when I was only scrolling through.

Mail unexpectedly quits when viewing certain messages

Learn how to troubleshoot if Mail unexpectedly quits when viewing a certain message or messages.

This can happen if the mail message is malformed or damaged in some way. In certain situations, Mail may unexpectedly quit when attempting to display the message.

If you select such a message, Mail may quit each time you open the application.

Use the steps below to open Mail without rendering any messages that are currently selected:


Open Mail and immediately hold the Shift key until Mail completely launches. This will cause Mail to launch without any Mail message or mailbox selected.
Follow the steps below to delete the problematic message:
Carefully drag the Message Viewer window pane until only the list of messages appears (or, double-click the pane). This will prevent any Mail message's content from being shown unless you double-click the message.
Click the problematic Mail message one time, then delete it (press the Delete key on your keyboard, or choose Message > Move to > Trash).