Apple Mail keeps crashing after Sierra update After updating to Sierra, directly after. The Mac Mail keeps crashing. I am trying to send an email and poof it crashes. It crashes randomly as well. Any way to re-install the app or do something without reseting my Mac?

Crashed Thread:        15  -[ComposeBackEnd _saveThreadUpdateAccount:mailbox:]  Dispatch queue: NSOperationQueue 0x600001648df0 :: NSOperation 0x608001e5b7b0 (QOS: USER_INTERACTIVE)

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Exception Note:        EXC_CORPSE_NOTIFY

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'This method must be called on the main thread'
abort() called
terminating with uncaught exception of type NSException


Log: http://pastebin.com/v2Gvw3J9
Have you guys tried Rebuilding the Mailbox? 

Mail App -> Mailbox -> Rebuild