iMac external display (EA232WMi) won't sleep I'm using an iMac 11,3 (27 inch, mid 2010) with an external display (an NEC EA232WMi).

Over the past week or so (beginning just prior to 10.9.2), when the iMac's display sleeps, the external display won't stay asleep. 

It keeps waking up.

I can see the power indicator repeatedly going back and forth between the "on" and "energy save" modes. When it wakes, it shows its usual message about not receiving any video input signal. The iMac's internal display doesn't (visibly) do anything at all.

It doesn't seem to be related to any apps-- if I reboot the iMac and leave it there at the login screen until the display sleeps, the same thing happens.

This only happens when the display is off but the iMac is still awake. When the iMac sleeps, everything seems normal.

If I move the external display to a different Mac (which is also running 10.9.2), the display sleeps normally, so it seems to be specific to the iMac.

I did an SMC reset and even zapped the PRAM (yes, voodoo) but they had no effect. What can I look at to figure out why the iMac keeps waking the external display?

Additional: Wondering if this might be related to an external device, I tried unplugging everything from USB. No change. Turned off Bluetooth? No change.

Update with some requested information:


Console logs. All that I get is the following. In this test, the main display slept at 10:10 AM and the external display problem appeared. I let it continue until 10:16 AM. These are all the messages that appeared in Console.

3/15/14 10:10:14.227 AM WindowServer[127]: device_generate_desktop_screenshot: authw 0x0(0), shield 0x7fa8028e4910(2001)
3/15/14 10:10:14.253 AM WindowServer[127]: device_generate_lock_screen_screenshot: authw 0x0(0), shield 0x7fa8028e4910(2001)
3/15/14 10:10:14.581 AM WindowServer[127]: device_generate_desktop_screenshot: authw 0x0(0), shield 0x7fa8028e4910(2001)
3/15/14 10:16:10.580 AM WindowServer[127]: handle_will_sleep_auth_and_shield_windows: Deferring.
3/15/14 10:16:10.582 AM WindowServer[127]: CGXDisplayDidWakeNotification [59971881496111]: posting kCGSDisplayDidWake

System report "Graphics" data. Looks OK to me, let me know if you see anything that seems wrong.

ATI Radeon HD 5750:

  Chipset Model:    ATI Radeon HD 5750
  Type: GPU
  Bus:  PCIe
  PCIe Lane Width:  x16
  VRAM (Total): 1024 MB
  Vendor:   ATI (0x1002)
  Device ID:    0x68a1
  Revision ID:  0x0000
  ROM Revision: 113-B9710C-238
  EFI Driver Version:   01.00.417
  Displays:
iMac:
  Display Type: LCD
  Resolution:   2560 x 1440
  Pixel Depth:  32-Bit Color (ARGB8888)
  Main Display: Yes
  Mirror:   Off
  Online:   Yes
  Built-In: Yes
EA232WMi:
  Resolution:   1920 x 1080 @ 60Hz (1080p)
  Pixel Depth:  32-Bit Color (ARGB8888)
  Display Serial Number:    1X312924NA  
  Mirror:   Off
  Online:   Yes
  Rotation: Supported
  Connection Type:  DisplayPort
  Television:   Yes



Update 2

In case it helps, I uploaded a system profile of my iMac which I generated using system_profiler -detailLevel mini.

Update 3

Since @Buscar웃 is deleting their answer, I'll add these details here:


"Wake on Network" is disabled
There's no screen lock (no password required to wake the Mac)
All sharing services have been disabled (several were active, including screen sharing and DVD sharing, bu disabling them had no effect).


Update 4

In case it's useful, the cycle time of the wake/sleep process is 8 seconds. Meaning, if I watch the display and its power indicator, this cycle repeats every 8 seconds:


Monitor shows its "no signal" screen
Monitor goes into power save mode
Monitor comes out of power save
Repeat


Update 5

I tried doing a safe boot; this also had no effect.

Update 6

Just for completeness I also used the external display's menu system to reset it to its factory defaults, but again, this had no effect.
Lets get more surgical here.

Facts are:
The external monitor stays in sleep mode on another Mac. It is unknowen if that mac has a Mavericks installed.

The Console report shows nothing unusual.

The Monitor configuration profile is still to be questioned (since it identifies the monitor as TV capable?

Recommended actions:

Use the PleaseSleep app
http://www.dragonone.com/products/macosx/pleasesleep/



Alternatively -Verify, Repair or replace the existing ICC profile

To verify use the Colorsync Utility and publish the current monitor profile

To repair use the ColorSyc utility and perform the repair of the external Monitors ICC

Alternatively download and install new ICC profile

New ICC profile for TFT monitor
http://www.tftcentral.co.uk/icc_profiles/nec_ea232wmi.icc