OSX Yosemite 10.10.2 MacMail freeze

Question

Since last Yosemite update 10.10.2 (february 2) MacMail freezes sometime after starting (it can take a few minutes).
I notice that it Freeze when the number of threads suddenly rise to the limit of 512!!
I get this in the error report:
    "Dispatch Thread Hard Limit Reached:  512  (too many dispatch threads blocked in synchronous operations)"
Also, if i try too exit Mail before it freezes, the process stays in the background and # of threads rise above 512
I have to "force quit" the process.
I tried to create a new user account and configure mail there.  Same problem after some time.
My mail account is of exchange type.
I tried also to create an account for an Exchange account that has just a few messages.  Seem to work fine.
Maybe i just have too many folders or too mani mails and Macmail no longer can handle this?   That would be a pain.

Answer 1

I have the exact same problem and am running...
OSX System Version: 10.10.2
Mac Mail Version 8.2 (2070.6)
Connecting to Microsoft Office 365
While Mac Mail is running I am getting the following message pairs appearing in the System Log at the rate of around 2 per second....
21/02/15 3:37:17.538 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2...etc
21/02/15 3:37:17.538 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
And I am regularly getting Mac Mail freezing.....with the dreaded spinning wheel.
21/02/15 3:57:06.641 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2/.....etc
21/02/15 3:57:06.641 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
21/02/15 3:57:06.891 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles[1083]) Could not find uid associated with service: 0: Undefined error: 0 505
21/02/15 3:57:06.892 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles) Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
21/02/15 3:57:07.071 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2/.....etc
21/02/15 3:57:07.071 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
21/02/15 3:57:07.291 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2/.....etc
21/02/15 3:57:07.291 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
21/02/15 3:57:07.749 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2/.....etc
21/02/15 3:57:07.749 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
21/02/15 3:57:07.990 pm fseventsd[27]: implementation_added_client : failed to add client for path /Users/ian/Library/Mail/V2/.....etc
21/02/15 3:57:07.990 pm fseventsd[27]: implementation_register_rpc: implementation_added_client() => 22
21/02/15 3:57:16.897 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles[1084]) Could not find uid associated with service: 0: Undefined error: 0 505
21/02/15 3:57:16.897 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles) Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
21/02/15 3:57:26.904 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles[1085]) Could not find uid associated with service: 0: Undefined error: 0 505
21/02/15 3:57:26.904 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles) Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
21/02/15 3:57:36.910 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles[1086]) Could not find uid associated with service: 0: Undefined error: 0 505
21/02/15 3:57:36.911 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles) Service only ran for 0 seconds. Pushing respawn out by 10 seconds.
21/02/15 3:57:46.919 pm com.apple.xpc.launchd[1]: (com.apple.mdworker.bundles[1087]) Could not find uid associated with service: 0: Undefined error: 0 505
....and the above couple of messages repeat for the next couple minute or two.
At this point Mac Mail is frozen (with the spinning wheel) and has to be restarted with a "force quit"
The first part of the "Problem Report" is....
Date/Time:       2015-02-21 16:07:25 +1300
OS Version:      10.10.2 (Build 14C109)
Architecture:    x86_64
Report Version:  21
Command:         Mail
Path:            /Applications/Mail.app/Contents/MacOS/Mail
Version:         8.2 (2070.6)
Build Version:   1
Project Name:    Mail
Source Version:  2070006000000000
Parent:          launchd [1]
PID:             803
Event:           hang
Duration:        1.00s (process was unresponsive for 580 seconds before sampling)
Steps:           11 (100ms sampling interval)
Hardware model:  MacBookPro10,1
Active cpus:     8
Fan speed:       2157 rpm
Timeline format: stacks are sorted chronologically
Use -i and -heavy to re-report with count sorting
Heaviest stack for the main thread of the target process:
  11  start + 1 (libdyld.dylib + 13769) [0x7fff8a2b55c9]
  11  NSApplicationMain + 1832 (AppKit + 10772) [0x7fff91c25a14]
  11  -[NSApplication run] + 711 (AppKit + 95752) [0x7fff91c3a608]
  11  ??? (Mail + 272704) [0x1023de940]
  11  -[NSApplication sendEvent:] + 4183 (AppKit + 1619025) [0x7fff91dae451]
  11  -[NSWindow sendEvent:] + 446 (AppKit + 1937774) [0x7fff91dfc16e]
  11  -[NSWindow _reallySendEvent:] + 12721 (AppKit + 7678488) [0x7fff92375a18]
  11  ??? (Mail + 405588) [0x1023ff054]
  11  -[NSTableView mouseDown:] + 620 (AppKit + 2026141) [0x7fff91e11a9d]
  11  -[NSTableView _performDragFromMouseDown:] + 218 (AppKit + 2032412) [0x7fff91e1331c]
  11  -[NSTableView _dragShouldBeginFromMouseDown:] + 402 (AppKit + 2034156) [0x7fff91e139ec]
  11  -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 505 (AppKit + 145511) [0x7fff91c46867]
  11  _NXDoMouseUpWindowOrdering + 324 (AppKit + 2035489) [0x7fff91e13f21]
  11  _NotifyEventLoopObservers + 155 (HIToolbox + 33068) [0x7fff9676d12c]
  11  HIApplication::EventObserver(unsigned int, OpaqueEventRef*, void*) + 238 (HIToolbox + 242928) [0x7fff967a04f0]
  11  HIApplication::HandleActivated(OpaqueEventRef*, unsigned char, OpaqueWindowPtr*) + 184 (HIToolbox + 248050) [0x7fff967a18f2]
  11  SetMenuBarObscured + 232 (HIToolbox + 248981) [0x7fff967a1c95]
  11  MenuBarInstance::Show(MenuBarAnimationStyle, unsigned char, unsigned char, unsigned char) + 474 (HIToolbox + 70156) [0x7fff9677620c]
  11  BroadcastToolboxMessage + 294 (HIToolbox + 189519) [0x7fff9679344f]
  11  HIS_XPC_CFNotificationCenterPostNotification + 111 (HIServices + 23324) [0x7fff8a2eeb1c]
  11  CFNotificationCenterPostNotification + 117 (CoreFoundation + 499157) [0x7fff915d5dd5]
  11  _CFXNotificationPost + 1270 (CoreFoundation + 64246) [0x7fff9156baf6]
  11  xpc_connection_send_message_with_reply_sync + 200 (libxpc.dylib + 38865) [0x7fff972827d1]
  11  semaphore_wait_trap + 10 (libsystem_kernel.dylib + 70938) [0x7fff8a27351a]
*11  semaphore_wait_continue + 0 (kernel + 1373536) [0xffffff800034f560]
Process:         Mail [803]
Path:            /Applications/Mail.app/Contents/MacOS/Mail
Architecture:    x86_64
Parent:          launchd [1]
UID:             894013837
Sudden Term:     Dirty
Task size:       107395 pages
Note:            Unresponsive for 580 seconds before sampling
Dispatch Thread Hard Limit Reached:  512  (too many dispatch threads blocked in synchronous operations)