Mail.app crashes, after Exchange server rebuild Our Exchange server was rebuilt following a hardware failure and this has resulted in the mailbox ID changing. Mail.app doesn't like this, and crashes as soon as it tries to check for new messages:

Process:               Mail [1174]
Path:                  /Applications/Mail.app/Contents/MacOS/Mail
Identifier:            com.apple.mail
Version:               8.2 (2102)
Build Info:            Mail-2102000000000000~1
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Mail [1174]
User ID:               501

Date/Time:             2015-07-14 08:59:48.324 +0100
OS Version:            Mac OS X 10.10.4 (14E46)
Report Version:        11
Anonymous UUID:        4F6F2F84-F869-25C2-1C87-B1246982BFD7


Time Awake Since Boot: 2200 seconds

Crashed Thread:        2  Dispatch queue: MFEWSAccountRequestResponseQueue :: NSOperation 0x600000697340 (QOS: UTILITY)

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

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Root Folder Id changed from AAMkADA5M2EyZWFiLWY1ZTctNDJlMS05MzQ1LTkyMDBkNTY2ZWEyMQAuAAAAAAA87sBtlAlTTJOPv8b7pvr6AQAUpHXDFMbMR5FSnLwG4BOUAAAAiMo7AAA= to AAMkADM0MjZkNGU4LTcwZGUtNDZhYi1hNjg4LTk0MGI5NWM4NzU3MgAuAAAAAAAcQlpkIwGwSb0hc5q+A04eAQB+EaxIvJoGTJt2RsDw05zJAAAAlpk5AAA=: once an account is created, the root folder id shouldn't change on the server'
abort() called
terminating with uncaught exception of type NSException


What's my best course of action? I have tried removing the 'Envelope' index files and rebuilding but with the same result. I don't want to completely wipe everything unless I absolutely have to, as I don't want to lose my local cache of messages (especially as they are no longer available on the server).
Buscar has the gist correct, though I would add a step: backup your ~/Library/Mail folder (OPTION-Drag it to the desktop) then delete the account.

One that is done add it back. If your old mail has vanished when the new account has been established just import the backed up mailboxes sitting on the Desktop.