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Headless Mac Mini Black Elements (blocks) when screen sharing

mattonthemoon

mattonthemoon

macrumors regular
Original poster
Feb 25, 2007
215
17
Toronto, ON
Hello,

I have a headless 2011 Mac Mini, i have noticed that when screen sharing with either, Apple Remote Desktop, Logmein, or another VNC app on my iPad i get a screen with black elements\bars. Moving windows around will get rid of the blocks, but it's very annoying.

I am wondering if there is something wrong with the mini and if i should return it, as i bought it last week.

Both my rMBP and 2011 Mac mini are running 10.8

Here's an attachement of an image i found on the internet showing the same issues as me.

Thanks.
 

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I'm also experiencing this very same issue when connecting to my headless Mac Mini (early 2012). It doesn't seem to be a client issue and unfortunately upgrading to Mountain Lion didn't fix the issue.
 
My old iMac used to do this when connecting via VLC. I just attributed it to the buffer not having a chance to get all the image blocks during the initial screen download time frame. Try enabling Screen Sharing on your RMBP and accessing from the Mini. Does something similar happen?
 
blevins321 said:
My old iMac used to do this when connecting via VLC. I just attributed it to the buffer not having a chance to get all the image blocks during the initial screen download time frame. Try enabling Screen Sharing on your RMBP and accessing from the Mini. Does something similar happen?
Click to expand...

I was thinking the same thing along those lines.

It only occurs when VNCing in to the mini. haven't tried vnc'ing to the rMBP yet.

I have, however, turned on the background settings to alternate every 5 minutes so it is constantly refreshing the entire screen even if no monitor is attached, and have gone the last 2 days without the issue. I figured this would be worth a shot since i can only seem to replicate the issue after the mini has been sitting with no remote user for a few hours, otherwise i cannot replicate it.
 
mattonthemoon said:
I am wondering if there is something wrong with the mini and if i should return it, as i bought it last week.
Thanks.
Click to expand...
Nothing wrong with your Mini. Mine does the same thing. Most of the time it's fine, but sometime it shows up with the whole image black. Moving a window around, or sometimes just quitting and restarting Screen Sharing fixes it. What resolution do you have set in Displays pref.
 
mattonthemoon said:
Hello,

I have a headless 2011 Mac Mini, i have noticed that when screen sharing with either, Apple Remote Desktop, Logmein, or another VNC app on my iPad i get a screen with black elements\bars. Moving windows around will get rid of the blocks, but it's very annoying.

I am wondering if there is something wrong with the mini and if i should return it, as i bought it last week.

Both my rMBP and 2011 Mac mini are running 10.8

Here's an attachement of an image i found on the internet showing the same issues as me.

Thanks.
Click to expand...

Just an update on this:

I ended up returning this mini to the Apple re-seller and purchasing as a refurb from the Apple website (as i originally intended but got too impatient).

In the 4 days this server has been live, i have not once been able to duplicate the issue i was having with the mac mini i originally posted about, see OP for details.

I am happy.

Here are the specs:

Headless i5 2.3GHz
16GB RAM
240 Vertex 3 SSD internal
1TB WD internal
 
I've been getting it more often since Mountain Lion with iTeleport. Air display doesn't have this issue. Haven't used screen sharing in a long, long time, though, as my iPad has been for monitor for two generations now.
 
I used to have this issue on my old Mac Pro before upgrading the ram. How much does the machine have? And have you checked activity monitor for page outs and ram usage?
 
swordfish5736 said:
I used to have this issue on my old Mac Pro before upgrading the ram. How much does the machine have? And have you checked activity monitor for page outs and ram usage?
Click to expand...

Could have been a RAM issue.

However this new mac mini has different RAM then the original. This mac mini not exhibiting the issue has 16GB of 1600MHz RAM, and 0 page outs.
 
Last edited:
I've had lots of problems screen sharing since upgrading to Mountain Lion on my 2010 Mac mini. It's headless, so I use iTeleport on my iPad and VNC on my MBP; both have had issues since the upgrade. I get the black blocks/bars using iTeleport, sometimes with the entire screen being black. Sharing the screen on my MBP is extremely laggy, as though I was on a remote, dialup network instead of my hard-wired LAN. I didn't use Lion, but on Snow Leopard, screen sharing was flawless. I'm hoping some sort of fix will come in a point update of ML.
 
I get this exact same problem. Headless mini, screen sharing from my 2012 i5 MBA.

My mini only has 2GB RAM. (2011 2.3 i5)

Looking at crucial, I can upgrade the RAM to 16GB pretty cheaply. Do you think this will help?

Im connecting to the mini over a gigabit wired network (AEBS) so I don't think thats the problem. Really would like to solve this as using the Mini is painful!
 
More RAM won't resolve it. :mad:
A HDMI cable connected to the mini won't resolve it. :mad:
A new Mac mini won't resolve it. :mad:

All of these I've tried. :mad:

In fact I've witnessed this on my PC if it has been disconnected from a monitor for a long time!

Here's what I did to finally fix the issue:

I have my desktop picture changing every 5 minutes or so. This seems to totally fix the issue! I haven't had the issue reappear once in several months.

It you'd like always having the same background image displayed (like I do) simply duplicate the image, put the copies in to its own folder, add this folder when selecting your background image, and select an interval for the "change picture every" option.

That's it. :D
 
Well I will try that. But I get this problem happening when I'm actually using it. I can connect in, everything is fine, and then it might start.

In addition to that, it is tediously laggy. Makes dragging and dropping almost impossible.
 
Hi all,

I have been having the same problem, It didnt take me long to figure out what the problem is and how to fix it, if you run your remote mac headless (no montor attached), screen sharing will be laggy straight away and will get worse within about a minute and in my opinion is to slow to use, as soon as plug a montior into the remote machine problem disapears and screen sharing is perfect, this is completely repeatable and I recommend everyone here try this first, I gather it has something to do with the GPU/iGPU in the machine you are remoting into.

My Setup

rMBP with Thunderbolt display as the client and a Mac Pro (with no monitir normally) as the host, tested over WiFi and over gigabit connection.

Mac Pro with no montor = lag and unusable screen sharing with every VNC client/server known to man, even ARD

Mac Pro with elcheapo montor attached = super fast screen sharing with every client/server including ARD

Both machines are running ML 10.8.2

Im about to make a VGA/DVI dongle with 3 100ohm resisters and see if this is enough to trick the GPU on the Mac Pro into thinking it has a monitor plugged into it, Ill post back here once I have tried it.

Cheers from AU
 
Same Issue

I've got this exact same issue, which is also completely solved by plugging in an external display - either HDMI or Thunderbolt.

Let us know how your resistor trick works - I'll have to use this to save some space (I hate having the extra screen laying around for a server I'm not actively using).
 
Can't find it now, but there was a similar thread with the exact same problem where someone solved it by simply connecting a video connector adapter, such as MDP to VGA, although I cannot remember the exact adapter.
 
I use remoter vnc to control my Mac pro using my iPad via wifi. it's so fast I can almost watch a movie! I highly recommend remoter vnc as the app !

also, try turning down the resolution, sometimes helps.
 
It seems that when you don't have a monitor connected, the GPU doesn't give you full performance. You can hack a dongle to make the mini think you have a monitor connected.

DONGLE-21.jpg


Here's a full writeup by MacStadium on how to maximize video performance for a headless mac mini.
 
fhall1 said:
similar article here http://blog.macminicolo.net/post/33839671756/build-a-dummy-dongle-for-a-headless-mac-mini
Click to expand...

So can somebody confirm that maxing out the GPU while headless increases performance of remote desktop (screen sharing)? I've never experienced so slow performance on any windows machine, so Ive actually considered installing windows server or a VM on the mini to see whether that increases the performance.

Is there no other way to have the headless one running on max GPU performance than hacking the dongle? I would prefer to not buy the dongle and transistor.

edit: not trolling :p

Changing backgroud every 5 minutes does not fix the black box issues for me.
 
Last edited:
The more I think about this the angrier I get. I think it's really annoying that you dont get full use of your GPU when using the computer headless? And that there is not a option for disabling that feature?

Anyway, I've got a HDMI - DVI adapter and resistors, but Im not skilled enough to understad the schematics of the DVI adapter.

On the VGA adapter, you use red analog ground to red analog. What whould that be on a DVI adapter? That is the offical HDMI-DVI adapter.

The "problem" is that the adapter does not have the pins I want to use, analog red and analog ground.

21rnkKukzFL._SL500_SS500_.jpg


Any skilled dude able to read up on wikipedia?

I actually have a total of 610 resistors. Yes, 610 of them. I just bought them - to fix this issue. The were only sold in packages of 610.
 
Last edited:
PaulKemp said:
So can somebody confirm that maxing out the GPU while headless increases performance of remote desktop (screen sharing)? I've never experienced so slow performance on any windows machine, so Ive actually considered installing windows server or a VM on the mini to see whether that increases the performance.

Is there no other way to have the headless one running on max GPU performance than hacking the dongle? I would prefer to not buy the dongle and transistor.

edit: not trolling :p

Changing backgroud every 5 minutes does not fix the black box issues for me.
Click to expand...


I totally agree especially that in my case I use sometimes the TV monitor connected though HDMI so I do not want to add another fake screen. More and more people start to notice this headless issue with Mini Mac so let us hope we will get a solution soon.
I am running some applications that would not run correctly when a physical screen is not connected to my mac mini so an headless mac mini in my case is not very useful ! My TV is connected to my mini mac 2012 ML though HDMI and when the TV monitor is on, Share Screen is quick and the applicatons do not bug ! Once TV is switched off and in System Preferences menu/displays you have no screen attached (so you are purely headless) then my applications start to bug.
The application I am talking about are Music Player running with Itunes11.
Anyway after more than 6 months of Moutain Lion this bug of the screen connected or not should be known by Apple.
Thanks
philoouu
 
Update: I can confirm that the performance is way better when the mini is connected to a monitor. I my case i've moved it to another room and its now working as it should.
 
PaulKemp said:
Update: I can confirm that the performance is way better when the mini is connected to a monitor. I my case i've moved it to another room and its now working as it should.
Click to expand...

Did you read the articles quoted above? All you need is an adapter to fool the Mini into thinking it's connected to a monitor.
 
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