Can't unlock Macbook after sleep until powering off and on The problem occurs after closing the lid of the laptop and it goes to sleep. When I open the lid, I am prompted for the password for my user as usual. When I press enter, there is no reaction. 

Now the only action I can do that gets a reaction is to push the power button twice to turn the screen off and then on. At this point, I am again able to enter the password, but this time when I push enter the masked password gets selected (the field doesn't shake). Same results for correct or incorrect passwords. Pushing the cancel or switch user button has no effect.

To log in again I cycle the power off and on. The problem recurs sometimes often (many times a day) and infrequently at other times.

I couldn't identify anything interesting in the logs; this is the leadup to me cycling the power in the system.log:

Apr 11 18:00:27 dresnick-mbp kernel[0]: kauth external resolver timed out (1 timeout(s) of 60 seconds).
Apr 11 18:00:31 dresnick-mbp.local identityservicesd[500]: &lt;IMMacNotificationCenterManager: 0x7f8153215230&gt;: notification observer: com.apple.iChat   notification: __CFNotification 0x7f8151611240 {name = _NSDoNotDisturbEnabledNotification}
Apr 11 18:00:32 dresnick-mbp.local WindowServer[132]: CGError post_notification(const CGSNotificationType, void *const, const size_t, const bool, const CGSRealTimeDelta, const int, const CGSConnectionID *const, const pid_t): Timed out 1.000 second wait for reply from "Firefox" for synchronous notification type 102 (kCGSDisplayWillSleep) (CID 0xa56b, PID 804)
Apr 11 18:00:32 dresnick-mbp.local WindowServer[132]: CGError post_notification(const CGSNotificationType, void *const, const size_t, const bool, const CGSRealTimeDelta, const int, const CGSConnectionID *const, const pid_t): Timed out 1.000 second wait for reply from "Microsoft Outlook" for synchronous notification type 102 (kCGSDisplayWillSleep) (CID 0xfa03, PID 465)
Apr 11 18:00:32 dresnick-mbp.local WindowServer[132]: CGError post_notification(const CGSNotificationType, void *const, const size_t, const bool, const CGSRealTimeDelta, const int, const CGSConnectionID *const, const pid_t): Timed out 1.000 second wait for reply from "Microsoft Lync" for synchronous notification type 102 (kCGSDisplayWillSleep) (CID 0x59a3, PID 477)
Apr 11 18:00:32 dresnick-mbp.local WindowServer[132]: device_generate_desktop_screenshot: authw 0x7f91f48773e0(2004), shield 0x7f91ed304810(2001)
Apr 11 18:00:32 dresnick-mbp.local WindowServer[132]: device_generate_lock_screen_screenshot: authw 0x7f91f48773e0(2004)[0, 0, 1440, 900] shield 0x7f91ed304810(2001), dev [1440,900]
Apr 11 18:00:42 dresnick-mbp.local loginwindow[74]: ERROR | -[LWBuiltInScreenLockAuthLion askForPasswordBuiltIn:] | Attempted to add an observer when already observing
Apr 11 18:00:42 dresnick-mbp.local WindowServer[132]: CGXDisplayDidWakeNotification [13749210101618]: posting kCGSDisplayDidWake
Apr 11 18:00:42 dresnick-mbp.local WindowServer[132]: handle_will_sleep_auth_and_shield_windows: Deferring.
Apr 11 18:00:46 dresnick-mbp.local identityservicesd[500]: &lt;IMMacNotificationCenterManager: 0x7f8153215230&gt;:    NC Disabled: NO


I'm running a MacBook Pro (Retina, 15-inch, Mid 2014), OS X 10.10.2
This was happening to me as well with very similar error message. When I saw it was saying it couldn't find a display I tried plugging in an external display.. sure enough it turned on. I think this happens if the screen goes to sleep while plugged into an external display. Pretty awful bug. Note that I am testing it by plugging in the identical display.. not sure if another display would fix it.