NSWorkspaceDidTerminateApplicationNotification crashes

So some of my users are getting crashes, and I think iv'e tracked it down to the NSWorkspaceDidTerminateApplicationNotification, I can't reproduce the crash at all so I'm not sure where to go?

here is the generated crash log, maybe I'm missing something obvious:

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000010
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Application Specific Information:
objc_msgSend() selector name: invalidate


Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
    0   libobjc.A.dylib                 0x00007fff816f211c objc_msgSend + 40
1   com.apple.Foundation            0x00007fff87ef58ea _nsnote_callback + 167
2   com.apple.CoreFoundation        0x00007fff869b3000 __CFXNotificationPost + 1008
3   com.apple.CoreFoundation        0x00007fff8699f578 _CFXNotificationPostNotification + 200
4   com.apple.Foundation            0x00007fff87eec84e -[NSNotificationCenter postNotificationName:object:userInfo:] + 101
5   com.apple.AppKit                0x00007fff878efb58 applicationStatusSubsystemCallback + 593
6   com.apple.LaunchServices        0x00007fff83523e6c LSScheduleNotificationReceiveMessageCallbackFunc(__CFMachPort*, void*, long, void*) + 184
7   com.apple.CoreFoundation        0x00007fff869cf68e __CFMachPortPerform + 366
8   com.apple.CoreFoundation        0x00007fff869a76e1 __CFRunLoopRun + 5201
9   com.apple.CoreFoundation        0x00007fff869a5dbf CFRunLoopRunSpecific + 575
10  com.apple.HIToolbox             0x00007fff80ef07ee RunCurrentEventLoopInMode + 333
11  com.apple.HIToolbox             0x00007fff80ef05f3 ReceiveNextEventCommon + 310
12  com.apple.HIToolbox             0x00007fff80ef04ac BlockUntilNextEventMatchingListInMode + 59
13  com.apple.AppKit                0x00007fff87232e64 _DPSNextEvent + 718
14  com.apple.AppKit                0x00007fff872327a9 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155
15  com.apple.AppKit                0x00007fff871f848b -[NSApplication run] + 395
16  com.apple.AppKit                0x开发者_运维技巧00007fff871f11a8 NSApplicationMain + 364

and here is the relevant code:

NSNotificationCenter *center = [[NSWorkspace sharedWorkspace] notificationCenter];
[center addObserver:self selector:@selector(appTerminated:) name:NSWorkspaceDidTerminateApplicationNotification object:nil];

- (void)appTerminated:(NSNotification *)note
{
    NSString *app = [NSString stringWithFormat:@"%@", [[note userInfo] objectForKey:@"NSApplicationName"]];

    if ([app isEqualToString:Somestring])
        {       
            //do something here            
        }
    }
}

If anyone could give me some pointers as to where to look, i'd be eternally grateful, I've been tearing my hair out for days now...

It looks like your window controller is getting deallocated while still being registered with the notification centre. You need to make sure the window controller is unregistered before deallocation. Otherwise, the notification centre will try to post a notification to a deallocated object, which can trigger an EXC_BAD_ACCESS exception.

For instance, in your window controller implementation:

- (void)dealloc {
    [[[NSWorkspace sharedWorkspace] notificationCenter] removeObserver:self];
    [super dealloc];
}

This will unregister the window controller with regard to every notification it’s registered with the notification centre.

Looks like a notification fired and tried to call an invalidate method on an object that has been deallocated. Turn on NSZombies and try again.