SecurityAgent terminating app due to uncaught exception

System is an iMac12,2 running Mountain Lion 10.8.2 with all updates. It was working fine earlier in the week. This AM, the user reported being unable to log in... we have a PolicyBanner, and when she hits the Accept button, the system churns for a minute and then returns her to the banner. She never gets to the login screen. Rebooting didn't help. Nor did fixing permissions or disk. I tried restoring the OS from media, resetting the PRAM, and moving /Library/Preferences. The Preferences folder does get rebuilt.

Here is the output of system.log after hitting Accept on the banner until the banner returns:

Feb 6 08:06:54 oscar SecurityAgent[127]: This is the first run
Feb 6 08:06:54 oscar SecurityAgent[127]: MacBuddy was run = 0
Feb 6 08:06:55 oscar SecurityAgent[127]: *** WARNING: -[NSImage compositeToPointperation:] is deprecated in MacOSX 10.8 and later. Please use -[NSImage drawAtPoint:fromRectperation:fraction:] instead.
Feb 6 08:06:55 oscar SecurityAgent[127]: *** WARNING: -[NSImage compositeToPoint:fromRectperation:] is deprecated in MacOSX 10.8 and later. Please use -[NSImage drawAtPoint:fromRectperation:fraction:] instead.
Feb 6 08:06:55 oscar SecurityAgent[127]: -[__NSCFString bytes]: unrecognized selector sent to instance 0x7faf5440e490
Feb 6 08:06:55 oscar SecurityAgent[127]: NSExceptionHandler has recorded the following exception:
NSInvalidArgumentException -- -[__NSCFString bytes]: unrecognized selector sent to instance 0x7faf5440e490
Stack trace: 0x10c9ac637 0x7fff8be1e3f0 0x7fff8c2366ea 0x7fff8c18e5ce 0x7fff8c18e3b8 0x7fff89dc61ff 0x7fff932481b4 0x7fff8f9a918a 0x10cb51919 0x10cb6010e 0x7fff8f9af6cb 0x7fff8f9ad767 0x7fff8f9ad41c 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d6e5b75 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d65b29d 0x7fff8c198a46 0x7fff8d65afdd 0x7fff8d65a634 0x7fff8d626a61 0x7fff8d7b0f44 0x7fff8d6e3b18 0x7fff8d6e3138 0x7fff8d6e2d1f 0x7fff8f9990c5 0x10cb5de50 0x10cb4ca94 0x7fff92aaaa2d 0x7fff92aa50b6 0x7fff92aaa0c8 0x7fff8c1420fe 0x7fff8c1416b2 0x7fff87dc00a4 0x7fff87dbfe42 0x7fff87dbfcd3 0x7fff8d623613 0x7fff8d622ed2 0x7fff8d61a283 0x10c97f544 0x7fff90cab7e1 0x1
Feb 6 08:06:55 oscar SecurityAgent[127]: An uncaught exception was raised
Feb 6 08:06:55 oscar SecurityAgent[127]: -[__NSCFString bytes]: unrecognized selector sent to instance 0x7faf5440e490
Feb 6 08:06:55 oscar SecurityAgent[127]: (
0 CoreFoundation 0x00007fff8c1a00a6 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff8be1e3f0 objc_exception_throw + 43
2 CoreFoundation 0x00007fff8c2366ea -[NSObject(NSObject) doesNotRecognizeSelector:] + 186
3 CoreFoundation 0x00007fff8c18e5ce ___forwarding___ + 414
4 CoreFoundation 0x00007fff8c18e3b8 _CF_forwarding_prep_0 + 232
5 CoreGraphics 0x00007fff89dc61ff CGDataProviderCreateWithCFData + 133
6 LoginUICore 0x00007fff932481b4 LUICreateImageFromJPEGData + 12
7 LoginUIKit 0x00007fff8f9a918a +[NSImage(LUIHelpers) imageForUserFromJPEGDatavatarType:] + 69
8 loginwindow 0x000000010cb51919 APMechanismSetResult + 31889
9 loginwindow 0x000000010cb6010e UserListOfUserWithPrimaryGroupGUID + 44376
10 LoginUIKit 0x00007fff8f9af6cb -[LUIUserListViewController stripView:itemForColumn:] + 525
11 LoginUIKit 0x00007fff8f9ad767 -[LUIStripView loadItemsForView] + 635
12 LoginUIKit 0x00007fff8f9ad41c -[LUIStripView viewWillDraw] + 160
13 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
14 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
15 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
16 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
17 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
18 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
19 AppKit 0x00007fff8d6e5b75 -[NSScrollView viewWillDraw] + 45
20 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
21 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
22 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
23 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
24 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
25 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
26 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
27 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
28 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
29 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
30 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
31 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
32 AppKit 0x00007fff8d65a634 -[NSView _sendViewWillDrawInRect:clipRootView:] + 1525
33 AppKit 0x00007fff8d626a61 -[NSView displayIfNeeded] + 1044
34 AppKit 0x00007fff8d7b0f44 -[NSNextStepFrame displayIfNeeded] + 84
35 AppKit 0x00007fff8d6e3b18 -[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 1377
36 AppKit 0x00007fff8d6e3138 -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 940
37 AppKit 0x00007fff8d6e2d1f -[NSWindow orderWindow:relativeTo:] + 159
38 LoginUIKit 0x00007fff8f9990c5 -[LUIWindowController showWindow] + 498
39 loginwindow 0x000000010cb5de50 UserListOfUserWithPrimaryGroupGUID + 35482
40 loginwindow 0x000000010cb4ca94 APMechanismSetResult + 11788
41 libdispatch.dylib 0x00007fff92aaaa2d _dispatch_barrier_sync_f_slow_invoke + 77
42 libdispatch.dylib 0x00007fff92aa50b6 _dispatch_client_callout + 8
43 libdispatch.dylib 0x00007fff92aaa0c8 _dispatch_main_queue_callback_4CF + 275
44 CoreFoundation 0x00007fff8c1420fe __CFRunLoopRun + 1614
45 CoreFoundation 0x00007fff8c1416b2 CFRunLoopRunSpecific + 290
46 HIToolbox 0x00007fff87dc00a4 RunCurrentEventLoopInMode + 209
47 HIToolbox 0x00007fff87dbfe42 ReceiveNextEventCommon + 356
48 HIToolbox 0x00007fff87dbfcd3 BlockUntilNextEventMatchingListInMode + 62
49 AppKit 0x00007fff8d623613 _DPSNextEvent + 685
50 AppKit 0x00007fff8d622ed2 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 128
51 AppKit 0x00007fff8d61a283 -[NSApplication run] + 517
52 SecurityAgent 0x000000010c97f544 SecurityAgent + 70980
53 libdyld.dylib 0x00007fff90cab7e1 start + 0
54 ??? 0x0000000000000001 0x0 + 1
)
Feb 6 08:06:55 oscar SecurityAgent[127]: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString bytes]: unrecognized selector sent to instance 0x7faf5440e490'
*** First throw call stack:
(
0 CoreFoundation 0x00007fff8c1a00a6 __exceptionPreprocess + 198
1 libobjc.A.dylib 0x00007fff8be1e3f0 objc_exception_throw + 43
2 CoreFoundation 0x00007fff8c2366ea -[NSObject(NSObject) doesNotRecognizeSelector:] + 186
3 CoreFoundation 0x00007fff8c18e5ce ___forwarding___ + 414
4 CoreFoundation 0x00007fff8c18e3b8 _CF_forwarding_prep_0 + 232
5 CoreGraphics 0x00007fff89dc61ff CGDataProviderCreateWithCFData + 133
6 LoginUICore 0x00007fff932481b4 LUICreateImageFromJPEGData + 12
7 LoginUIKit 0x00007fff8f9a918a +[NSImage(LUIHelpers) imageForUserFromJPEGDatavatarType:] + 69
8 loginwindow 0x000000010cb51919 APMechanismSetResult + 31889
9 loginwindow 0x000000010cb6010e UserListOfUserWithPrimaryGroupGUID + 44376
10 LoginUIKit 0x00007fff8f9af6cb -[LUIUserListViewController stripView:itemForColumn:] + 525
11 LoginUIKit 0x00007fff8f9ad767 -[LUIStripView loadItemsForView] + 635
12 LoginUIKit 0x00007fff8f9ad41c -[LUIStripView viewWillDraw] + 160
13 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
14 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
15 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
16 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
17 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
18 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
19 AppKit 0x00007fff8d6e5b75 -[NSScrollView viewWillDraw] + 45
20 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
21 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
22 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
23 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
24 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
25 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
26 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
27 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
28 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
29 AppKit 0x00007fff8d65b29d __22-[NSView viewWillDraw]_block_invoke_0 + 307
30 CoreFoundation 0x00007fff8c198a46 __NSArrayEnumerate + 582
31 AppKit 0x00007fff8d65afdd -[NSView viewWillDraw] + 244
32 AppKit 0x00007fff8d65a634 -[NSView _sendViewWillDrawInRect:clipRootView:] + 1525
33 AppKit 0x00007fff8d626a61 -[NSView displayIfNeeded] + 1044
34 AppKit 0x00007fff8d7b0f44 -[NSNextStepFrame displayIfNeeded] + 84
35 AppKit 0x00007fff8d6e3b18 -[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 1377
36 AppKit 0x00007fff8d6e3138 -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 940
37 AppKit 0x00007fff8d6e2d1f -[NSWindow orderWindow:relativeTo:] + 159
38 LoginUIKit 0x00007fff8f9990c5 -[LUIWindowController showWindow] + 498
39 loginwindow 0x000000010cb5de50 UserListOfUserWithPrimaryGroupGUID + 35482
40 loginwindow 0x000000010cb4ca94 APMechanismSetResult + 11788
41 libdispatch.dylib 0x00007fff92aaaa2d _dispatch_barrier_sync_f_slow_invoke + 77
42 libdispatch.dylib 0x00007fff92aa50b6 _dispatch_client_callout + 8
43 libdispatch.dylib 0x00007fff92aaa0c8 _dispatch_main_queue_callback_4CF + 275
44 CoreFoundation 0x00007fff8c1420fe __CFRunLoopRun + 1614
45 CoreFoundation 0x00007fff8c1416b2 CFRunLoopRunSpecific + 290
46 HIToolbox 0x00007fff87dc00a4 RunCurrentEventLoopInMode + 209
47 HIToolbox 0x00007fff87dbfe42 ReceiveNextEventCommon + 356
48 HIToolbox 0x00007fff87dbfcd3 BlockUntilNextEventMatchingListInMode + 62
49 AppKit 0x00007fff8d623613 _DPSNextEvent + 685
50 AppKit 0x00007fff8d622ed2 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 128
51 AppKit 0x00007fff8d61a283 -[NSApplication run] + 517
52 SecurityAgent 0x000000010c97f544 SecurityAgent + 70980
53 libdyld.dylib 0x00007fff90cab7e1 start + 0
54 ??? 0x0000000000000001 0x0 + 1
)
Feb 6 08:06:55 oscar coresymbolicationd[517]: /Library/Caches/com.apple.coresymbolicationd/data did not validate, resetting cache
Feb 6 08:06:55 oscar ReportCrash[516]: DebugSymbols was unable to start a spotlight query: spotlight is not responding or disabled.
Feb 6 08:06:59 oscar ReportCrash[516]: failed looking up LS service ( scCreateSystemService returned MACH_PORT_NULL, called from SetupCoreApplicationServicesCommunicationPort, so using client-side NULL calls.
Feb 6 08:06:59 oscar ReportCrash[516]: LaunchServices/5123589: Unable to lookup coreservices session port for session 0x186a0 uid=0 euid=0
Feb 6 08:06:59 oscar ReportCrash[516]: failed looking up LS service ( scCreateSystemService returned MACH_PORT_NULL, called from SetupCoreApplicationServicesCommunicationPort, so using client-side NULL calls.
Feb 6 08:06:59 oscar ReportCrash[516]: LaunchServices/5123589: Unable to lookup coreservices session port for session 0x186a0 uid=0 euid=0
Feb 6 08:06:59 oscar ReportCrash[516]: failed looking up LS service ( scCreateSystemService returned MACH_PORT_NULL, called from SetupCoreApplicationServicesCommunicationPort, so using client-side NULL calls.
Feb 6 08:06:59 oscar ReportCrash[516]: LaunchServices/5123589: Unable to lookup coreservices session port for session 0x186a0 uid=0 euid=0
Feb 6 08:06:59 oscar ReportCrash[516]: failed looking up LS service ( scCreateSystemService returned MACH_PORT_NULL, called from SetupCoreApplicationServicesCommunicationPort, so using client-side NULL calls.
Feb 6 08:06:59 oscar ReportCrash[516]: LaunchServices/5123589: Unable to lookup coreservices session port for session 0x186a0 uid=0 euid=0
Feb 6 08:06:59 oscar ReportCrash[516]: failed looking up LS service ( scCreateSystemService returned MACH_PORT_NULL, called from SetupCoreApplicationServicesCommunicationPort, so using client-side NULL calls.
Feb 6 08:06:59 oscar ReportCrash[516]: LaunchServices/5123589: Unable to lookup coreservices session port for session 0x186a0 uid=0 euid=0
Feb 6 08:06:59 oscar com.apple.SecurityServer[20]: Engine:uthorize: Rule::evaluate returned 4294907288 returning errAuthorizationInternal
Feb 6 08:06:59 oscar loginwindow[47]: Login Window - Returned from Security Agent
Feb 6 08:06:59 oscar com.apple.launchd[1] (com.apple.SecurityAgent.00000000-0000-0000-0000-0000000186A3[127]): Job appears to have crashed: Abort trap: 6
Feb 6 08:06:59 oscar loginwindow[47]: AuthorizationRef doesn't have a username (<LoginAuthRefMgr: 0x7ffc0bc1fe80>). Exiting.
Feb 6 08:06:59 oscar WindowServer[88]: CGXRestartSessionWorkspace: session workspace exited for session 256 (on console)
Feb 6 08:06:59 oscar WindowServer[88]: Session 256 released (1 references)
Feb 6 08:06:59 oscar WindowServer[88]: Session 256 released (0 references)
Feb 6 08:06:59 oscar WindowServer[88]: loginwindow connection closed; closing server.
Feb 6 08:06:59 oscar loginwindow[518]: Login Window Application Started
Feb 6 08:06:59 oscar WindowServer[520]: Server is starting up
Feb 6 08:06:59 oscar WindowServer[520]: Session 256 retained (2 references)
Feb 6 08:06:59 oscar WindowServer[520]: Session 256 released (1 references)
Feb 6 08:06:59 oscar WindowServer[520]: Session 256 retained (2 references)
Feb 6 08:06:59 oscar WindowServer[520]: init_page_flip: page flip mode is on
Feb 6 08:06:59 oscar WindowServer[520]: mux_initialize: Couldn't find any matches
Feb 6 08:06:59 oscar WindowServer[520]: GLCompositor enabled for tile size [256 x 256]
Feb 6 08:06:59 oscar WindowServer[520]: CGXGLInitMipMap: mip map mode is on
Feb 6 08:06:59 oscar WindowServer[520]: WSMachineUsesNewStyleMirroring: false
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x042c0080: GL mask 0x1; bounds (0, 0)[2560 x 1440], 36 modes available
Main, Active, on-line, enabled, built-in, boot, Vendor 610, Model b002, S/N 0, Unit 0, Rotation 0
UUID 0x000006100000b00200000000042c0080
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f0040: GL mask 0x10; bounds (0, 0)[0 x 0], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 4, Rotation 0
UUID 0xffffffffffffffffffffffff003f0040
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003f: GL mask 0x8; bounds (0, 0)[0 x 0], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 3, Rotation 0
UUID 0xffffffffffffffffffffffff003f003f
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003e: GL mask 0x4; bounds (0, 0)[0 x 0], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 2, Rotation 0
UUID 0xffffffffffffffffffffffff003f003e
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003d: GL mask 0x2; bounds (0, 0)[0 x 0], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 1, Rotation 0
UUID 0xffffffffffffffffffffffff003f003d
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x4 for display 0x042c0080
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x5 for display 0x003f0040
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x6 for display 0x003f003f
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x7 for display 0x003f003e
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x8 for display 0x003f003d
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x042c0080: GL mask 0x1; bounds (0, 0)[2560 x 1440], 36 modes available
Main, Active, on-line, enabled, built-in, boot, Vendor 610, Model b002, S/N 0, Unit 0, Rotation 0
UUID 0x000006100000b00200000000042c0080
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f0040: GL mask 0x10; bounds (3584, 0)[1 x 1], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 4, Rotation 0
UUID 0xffffffffffffffffffffffff003f0040
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003f: GL mask 0x8; bounds (3585, 0)[1 x 1], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 3, Rotation 0
UUID 0xffffffffffffffffffffffff003f003f
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003e: GL mask 0x4; bounds (3586, 0)[1 x 1], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 2, Rotation 0
UUID 0xffffffffffffffffffffffff003f003e
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003d: GL mask 0x2; bounds (3587, 0)[1 x 1], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 1, Rotation 0
UUID 0xffffffffffffffffffffffff003f003d
Feb 6 08:06:59 oscar WindowServer[520]: CGXPerformInitialDisplayConfiguration
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x042c0080: MappedDisplay Unit 0; Vendor 0x610 Model 0xb002 S/N 0 Dimensions 23.50 x 13.23; online enabled built-in, Bounds (0,0)[2560 x 1440], Rotation 0, Resolution 1
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f0040: MappedDisplay Unit 4; Vendor 0xffffffff Model 0xffffffff S/N -1 Dimensions 0.00 x 0.00; offline enabled, Bounds (3584,0)[1 x 1], Rotation 0, Resolution 1
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003f: MappedDisplay Unit 3; Vendor 0xffffffff Model 0xffffffff S/N -1 Dimensions 0.00 x 0.00; offline enabled, Bounds (3585,0)[1 x 1], Rotation 0, Resolution 1
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003e: MappedDisplay Unit 2; Vendor 0xffffffff Model 0xffffffff S/N -1 Dimensions 0.00 x 0.00; offline enabled, Bounds (3586,0)[1 x 1], Rotation 0, Resolution 1
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x003f003d: MappedDisplay Unit 1; Vendor 0xffffffff Model 0xffffffff S/N -1 Dimensions 0.00 x 0.00; offline enabled, Bounds (3587,0)[1 x 1], Rotation 0, Resolution 1
Feb 6 08:06:59 oscar WindowServer[520]: GLCompositor: GL renderer id 0x01021b05, GL mask 0x0000001f, accelerator 0x00004837, unit 0, caps QEX|QGL|MIPMAP, vram 1024 MB
Feb 6 08:06:59 oscar WindowServer[520]: GLCompositor: GL renderer id 0x01021b05, GL mask 0x0000001f, texture units 8, texture max 16384, viewport max {16384, 16384}, extensions FPRG|NPOT|GLSL|FLOAT
Feb 6 08:06:59 oscar loginwindow[518]: **DMPROXY** Found `/System/Library/CoreServices/DMProxy'.
Feb 6 08:06:59 oscar WindowServer[520]: Created shield window 0x9 for display 0x042c0080
Feb 6 08:06:59 oscar WindowServer[520]: Display 0x042c0080: MappedDisplay Unit 0; ColorProfile { 2, "iMac"}; TransferFormula (1.000000, 1.000000, 1.000000)
Feb 6 08:06:59 oscar launchctl[522]: com.apple.findmymacmessenger: Already loaded
Feb 6 08:06:59 oscar com.apple.SecurityServer[20]: Session 100008 created
Feb 6 08:06:59 oscar hidd[52]: CGSShutdownServerConnections: Detaching application from window server
Feb 6 08:06:59 oscar hidd[52]: CGSDisplayServerShutdown: Detaching display subsystem from window server
Feb 6 08:06:59 oscar loginwindow[518]: Login Window Started Security Agent
Feb 6 08:06:59 oscar helpd[528]: Could not find access page in directory /Library/Documentation/Help/Norton Help Scripts
Feb 6 08:07:00 --- last message repeated 1 time ---
Feb 6 08:07:00 oscar locationd[532]: Incorrect NSStringEncoding value 0x8000100 detected. Assuming NSASCIIStringEncoding. Will stop this compatiblity mapping behavior in the near future.
Feb 6 08:07:00 oscar locationd[532]: NOTICE,Location icon should now be in state 0
Feb 6 08:07:00 oscar UserEventAgent[525]: cannot find useragent 1102
Feb 6 08:07:00 oscar ReportCrash[516]: Saved crash report for SecurityAgent[127] version 7.0 (55116.8) to /Library/Logs/DiagnosticReports/SecurityAgent_2013-02-06-080700_oscar.crash
Feb 6 08:07:00 oscar ReportCrash[516]: Removing excessive log: file://localhost/Library/Logs/DiagnosticReports/SecurityAgent_2013-02-06-060906 _oscar.crash
Feb 6 08:07:00 oscar WindowServer[520]: 3891612: App SecurityAgent cannot order in untagged windows before login.
Feb 6 08:07:00 oscar WindowServer[520]: kCGErrorInvalidOperation: CGXOrderWinsAndPanels: error ordering window
Feb 6 08:07:01 oscar com.apple.launchd.peruser.92[513]: Background: Bug: 12C60: launchd + 80370 [7DCC9489-2DF5-3807-83FA-EF5666EE8078]: 0x0
Feb 6 08:07:01 oscar com.apple.launchd.peruser.92[513]: Background: This API can only be used by a process running within an Aqua session.
Feb 6 08:07:01 oscar SecurityAgent[530]: spawn_via_launchd() failed, errno=5 label=[0x0-0x12012].com.apple.AppleSpell path=/System/Library/Services/AppleSpell.service/Contents/MacOS/AppleSpell flags=0
Feb 6 08:07:01 --- last message repeated 1 time ---
Feb 6 08:07:01 oscar SecurityAgent[530]: Error launching spell checker for U.S. English: Error Domain=NSCocoaErrorDomain Code=256 "The application “AppleSpell.service” could not be launched because a miscellaneous error occurred (OSStatus -10810)." UserInfo=0x7ff61bc0c2e0 {NSURL=file://localhost/System/Library/Services/AppleSpell.service/, NSLocalizedDescription=The application “AppleSpell.service” could not be launched because a miscellaneous error occurred (OSStatus -10810)., NSUnderlyingError=0x7ff61bc0bbe0 "The operation couldn’t be completed. (OSStatus error -10810.)"}
Feb 6 08:07:01 oscar WindowServer[520]: **DMPROXY** (2) Found `/System/Library/CoreServices/DMProxy'.
Feb 6 08:07:01 oscar WindowServer[520]: Display 0x042c0080: MappedDisplay Unit 0; ColorProfile { 2, "iMac"}; TransferFormula (1.000000, 1.000000, 1.000000)
Feb 6 08:07:02 --- last message repeated 1 time ---
Feb 6 08:07:02 oscar WindowServer[520]: MPAccessSurfaceForDisplayDevice: Set up page flip mode on display 0x042c0080 device: 0x101ca8320 isBackBuffered: 1 numComp: 3 numDisp: 3
Feb 6 08:07:02 oscar CVMServer[91]: Check-in to the service com.apple.cvmsCompAgent_x86_64 failed. This is likely because you have either unloaded the job or the MachService has the ResetAtClose attribute specified in the launchd.plist. If present, this attribute should be removed.

Additional data point... this happened on another Mac, one on which File Vault was enabled. A user who unlocks the disk winds up logged in after being prompted for their Apple ID and being told there was some problem and do they want to re-open applications that were open.

This turned out to be a corrupt user avatar... 'dscl . -delete /Users/username JPEGPhoto' is the solution.