I am also having this crashing problem. I am running lion on a 2010 mac mini. My iPhoto library is kept on an external drive. I just upgraded to iPhoto 11 and everytime I try to enable photo stream the app crashes. I have tried all the above suggestions, including re-installing iphoto from the Mac App store. Below are the first 50 lines of the error message. Any help would be greatly appreciated.
Process: iPhoto [430]
Path: /Applications/iPhoto.app/Contents/MacOS/iPhoto
Identifier: com.apple.iPhoto
Version: 9.2.1 (9.2.1)
Build Info: iPhotoProject-628000000000000~1
App Item ID: 408981381
App External ID: 4641130
Code Type: X86 (Native)
Parent Process: launchd [160]
Date/Time: 2011-11-02 22:33:22.628 -0500
OS Version: Mac OS X 10.7.2 (11C74)
Report Version: 9
Interval Since Last Report: 526713 sec
Crashes Since Last Report: 9
Per-App Interval Since Last Report: 4439 sec
Per-App Crashes Since Last Report: 8
Anonymous UUID: 8147E0FC-2622-4A56-920E-44498E48B55B
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
VM Regions Near 0:
--> __PAGEZERO 0000000000000000-0000000000001000 [ 4K] ---/--- SM=NUL /Applications/iPhoto.app/Contents/MacOS/iPhoto
__TEXT 0000000000001000-0000000000d1b000 [ 13.1M] r-x/rwx SM=COW /Applications/iPhoto.app/Contents/MacOS/iPhoto
Application Specific Information:
objc[430]: garbage collection is OFF
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 com.apple.iPhoto 0x00824501 0x1000 + 8533249
1 com.apple.iPhoto 0x001678d6 0x1000 + 1468630
2 com.apple.Foundation 0x91bdff49 __-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_1 + 49
3 com.apple.CoreFoundation 0x95508ff3 ___CFXNotificationPost_block_invoke_1 + 275
4 com.apple.CoreFoundation 0x954d3d78 _CFXNotificationPost + 2776
5 com.apple.Foundation 0x91bcb136 -[NSNotificationCenter postNotificationName:object:userInfo:] + 92
6 com.apple.Foundation 0x91be03ca -[NSNotificationCenter postNotificationName:object:] + 55
7 com.apple.iPhoto 0x0016716a 0x1000 + 1466730
8 com.apple.iPhoto 0x00167111 0x1000 + 1466641
9 com.apple.iPhoto 0x0015c6f4 0x1000 + 1423092
10 com.apple.CoreFoundation 0x95520e1d __invoking___ + 29
11 com.apple.CoreFoundation 0x95520d59 -[NSInvocation invoke] + 137
12 com.apple.RedRock 0x01d62e61 -[RKInvoker _invokeTarget:] + 33
13 com.apple.CoreFoundation 0x9551e091 -[NSObject performSelector:withObject:] + 65
14 com.apple.Foundation 0x91c1cf64 __NSThreadPerformPerform + 503
15 com.apple.CoreFoundation 0x9549584f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
16 com.apple.CoreFoundation 0x95495206 __CFRunLoopDoSources0 + 246
17 com.apple.CoreFoundation 0x954bf0d8 __CFRunLoopRun + 1112
18 com.apple.CoreFoundation 0x954be8ec CFRunLoopRunSpecific + 332
19 com.apple.CoreFoundation 0x954be798 CFRunLoopRunInMode + 120
20 com.apple.HIToolbox 0x93bcca7f RunCurrentEventLoopInMode + 318
21 com.apple.HIToolbox 0x93bd3d9b ReceiveNextEventCommon + 381
22 com.apple.HIToolbox 0x93bd3c0a BlockUntilNextEventMatchingListInMode + 88
23 com.apple.AppKit 0x97b27040 _DPSNextEvent + 678
24 com.apple.AppKit 0x97b268ab -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 113
25 com.apple.AppKit 0x97b22c22 -[NSApplication run] + 911
26 com.apple.AppKit 0x97db718a NSApplicationMain + 1054
27 com.apple.iPhoto 0x0001159a 0x1000 + 66970
28 com.apple.iPhoto 0x00010a29 0x1000 + 64041
Thread 1:: Dispatch queue: com.apple.libdispatch-manager
0 libsystem_kernel.dylib 0x91bbc90a kevent + 10
1 libdispatch.dylib 0x9a5bbc58 _dispatch_mgr_invoke + 969
2 libdispatch.dylib 0x9a5ba6a7 _dispatch_mgr_thread + 53