After up-date to Yosemite, mail crashes on opening

Question

I just upgraded to Yosemite on a late 2009 iMac (3.06 GHz Intel Core 2 Duo; 16 GB 1067 MHz DDR3 memory.
How do I solve the problem of mail crashing. Here's top of crash report:
Process:               Mail [752]
Path:                  /Applications/Mail.app/Contents/MacOS/Mail
Identifier:            com.apple.mail
Version:               8.0 (1990.1)
Build Info:            Mail-1990001000000000~3
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           Mail [752]
User ID:               501
Date/Time:             2014-10-17 15:39:16.530 -0400
OS Version:            Mac OS X 10.10 (14A389)
Report Version:        11
Anonymous UUID:        17E54C50-3AA9-5D1B-8977-92279388F7EF
Time Awake Since Boot: 2100 seconds
Crashed Thread:        2  Dispatch queue: NSOperationQueue 0x60800023a200 :: NSOperation 0x608000648160 (QOS: UTILITY)
Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000
Application Specific Information:
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Absolute path passed into -[MFPOPAccount mailboxForRelativePath:isFilesystemPath:create:]: /Users/garywerner/Library/Mail/V2/[email protected]/Drafts.mbox'
abort() called
terminating with uncaught exception of type NSException

Answer 1

that's it - I ran the updater - and I believe I have been able to use it all day without the program crashing when it encounters an attachment.
one goofy thing I noticed, for the first time, there appear to be two applications folders on my start-up drive (1) in my user folder (2) in the "main" hard drive folder.
MAIL is in both - I believe the "main" one was updated; when I turned on the "user" MAIL it crashed when I opened an eMail with an attachment; when I opened the same eMail with the "main" mail there was no problem.
now what does this tell us?
thanks again!
will