5K iMac start up screen flicker video - Is this normal?

[yustas]

Is this normal? It does the same thing when it comes back from sleep, but not always, sometimes it does that, sometimes it does not. Here is the video: https://www.dropbox.com/s/txuo5kkswtmn5h7/Video.MOV?dl=0

Thanks.

 

[redheeler]

I get the first flash on the black screen with progress bar and believe it is normal, but not the second one when the desktop shows up.

Does it always do the second one when you boot up? I only tested it once with automatic login turned on since I normally have it off.

Wouldn't hurt to try a PRAM reset.

 

[yustas]

Does it always do the second one when you boot up? I only tested it once with automatic login turned on since I normally have it off.

Wouldn't hurt to try a PRAM reset.

Yes, it always does it on the boot up. It also does the same thing when it comes back from sleep, but not always when it comes back from sleep.

I did the PRAM reset before taking that video.

Edit: P.S. By the way, my config is exactly the same as yours.

 

[ZMacintosh]

almost seems like a Yosemite thing. I've seen something similar using a Thunderbolt display and a 2013 Mac Pro.

have you tried maybe booting to a clean install OS On a usb drive or booting into Recovery mode just to see if it does it on those screens as well?

 

[yustas]

almost seems like a Yosemite thing. I've seen something similar using a Thunderbolt display and a 2013 Mac Pro.

have you tried maybe booting to a clean install OS On a usb drive or booting into Recovery mode just to see if it does it on those screens as well?

I have not tried that, but I did "Verify Disk Permissions" and got the following: User differs on "private/var/db/displaypolicyd"; should be 0; user is 244. Group differs on private/var/db/displaypolicyd"; should be 0; user is 244.

Fixing it, did not make it go away. I checked my 21 inch iMac and it has the same thing, but the screen on it does not flicker.

I have two displays connect to the 5K, BenQ and Asus. I disconnected both (they are connected via thunderbolt-to-minidisplay adapter cables), powered down the 5K, disconnected the power cable and after 10 minutes boot it up again. This time, there was no flicker.

So, it seems that it has to do with connecting additional monitors to it, but the question is: Is it a normal behavior when other displays connected to it or not?

Thanks.

 

[redheeler]

I have not tried that, but I did "Verify Disk Permissions" and got the following: User differs on "private/var/db/displaypolicyd"; should be 0; user is 244. Group differs on private/var/db/displaypolicyd"; should be 0; user is 244.

I got that as well when verifying permissions through Disk Utility. Seems to be normal.

Fixing it, did not make it go away. I checked my 21 inch iMac and it has the same thing, but the screen on it does not flicker.

I have two displays connect to the 5K, BenQ and Asus. I disconnected both (they are connected via thunderbolt-to-minidisplay adapter cables), powered down the 5K, disconnected the power cable and after 10 minutes boot it up again. This time, there was no flicker.

So, it seems that it has to do with connecting additional monitors to it, but the question is: Is it a normal behavior when other displays connected to it or not?

Thanks.

Are you talking about the second one when the desktop appears, or the first one during the progress bar phase. The first is the only one I see, and I don't have an external display connected.

 

[yustas]

Are you talking about the second one when the desktop appears, or the first one during the progress bar phase. The first is the only one I see, and I don't have an external display connected.

The second one. When the desktop appears, it briefly disappears on the first load and then loads again.