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Issue 7: Garbled screen with multiple monitors or large display
7 people starred this issue and may be notified of changes. Back to list
Status:  Started

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Reported by, Sep 17, 2007
What steps will reproduce the problem?
1.Connect to a server with extended desktop enabled 

What is the expected output? What do you see instead?
Garbled/black screen

What version of the product are you using? On what operating system?
0.2, Win2k3

Please provide any additional information below.
After disabling extended desktop VNSea works excellent!
Sep 17, 2007
Project Member #1
What VNC server software are you using?
Status: Accepted
Owner: crflit
Sep 17, 2007
I am using the latest version od RealVNC - VNC Server Free Edition 4.1.2

Sep 17, 2007
Project Member #3
Comments from a duplicate issue. Apparently this issue applies to both windows and mac servers.

What steps will reproduce the problem?
1. Connecting to a remote desktop with 2 displays

What is the expected output? What do you see instead?

Expect to see desktop on remote computer. Instead I see part of the Desktop
Background but no windows. In addition the screen freaks out as though it's
trying to load something else or refresh but is unable to do so.

What version of the product are you using? On what operating system?

VNsea 0.2 on iPhone 1.0.2 over Apple Remote Desktop on 10.4.10

Please provide any additional information below.

I tried at home on an almost identical system and it worked ok. The only
difference between my work and home computer is that work had dual
displays. Setting the work computer to mirror the displays allows VNsea to
work as  expected.
Sep 17, 2007
Here's a screen capture from my garbles connection.
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Sep 17, 2007
Having the same issue.  I don't have 2 displays, just a big monitor.  It fails when the desktop resolution is set to 
1920x1200 and works when the desktop resolution is set to 1600x1200.
Sep 17, 2007
I can confirm the resolution issue...when I tried adjusting the resolution on my 24' iMac from 1920x1200 down 
to 1600x1200, everything was fine. Moving back up to 1920x1200 still garbles the screen.
Sep 18, 2007
Just to help narrow it down a bit... my MacMini runs at 1680x1050 (max resolution of
the monitor I'm using) and VNsea doesn't crash.  Using Vine on the MacMini.
Sep 18, 2007
Project Member #8
Thanks for the screenshot! It certainly helps me understand the bug.
Sep 18, 2007
I'm getting this problem too. I've attached two screenshots - it basically shows
these colorbands, alternating, and eventually crashes and returns me to the springboard.

Windows XP Professional

VNC: RealVNC Free Edition, v4.1.2 (same exact one as the OP)

Also, to note, I am using UltraMon (multiple desktop management software) on my
windows box. Once I set it to disable the secondary monitor, VNSea works just fine.
Great job!! But multiple monitor support would be ideal :)
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Sep 18, 2007
Project Member #10
How bizarre! Thanks for the screenshots and comments, atomjack.
Labels: -Priority-Medium Priority-High
Sep 19, 2007
I am having the exact same issue. I have two monitors, one's at 1920x1200, the other's at 1280x1024. If I 
connect to a machine with just 1280x1024 it works just fine.
Sep 20, 2007
Project Member #12
I'm thinking that maybe it's not the multiple monitors but the size of the combined desktop that is the 
problem. Perhaps there is a limit to the size of a UIView on the iPhone, beyond which it goes nuts.
Sep 21, 2007
Hi crflit.

Your theory is correct.

I have two monitors running on Mac Os x 10.4 on a machine running Remote Desktop.
When i tried to connect using vnsea the displayed was garbled. i lowered the
resolution on the desktop to 800 * 600 and 640 * 480 and i could then connect without

Sep 24, 2007
Project Member #14
rcoppa, thanks for verifying that for me!
Sep 25, 2007
Project Member #15
(No comment was entered for this change.)
Labels: Milestone-Release1.0
Sep 27, 2007
no worries. thanks for a great piece of software :)
Oct 8, 2007
Same here.

Works @ 1680x1050 but not @ 1920x1280 on my PC (dell inspiron 8500)

PS: How do I scroll in the app ? lol
Oct 8, 2007

Found how to scroll. :D
Hold one finger on your screen, and scroll with the other.
Oct 16, 2007
Any movement or new info on this particular issue?

Or has it been diagnosed as a limitation on iPhone's end and there's no fix in sight?
Oct 22, 2007
Project Member #20
You'll see the status change as the defect progresses through the workflow. Right now this defect is targeted 
at the 1.0 release.
Oct 23, 2007
Project Member #21
Improved summary.
Summary: Garbled screen with multiple monitors or large display
Oct 24, 2007
Gotcha...thanks for clearing that up!
Oct 30, 2007
Just a note, but I am also having this problem using the built in screen sharing
server in Leopard. I just see a bunch of lines on the display. 
Nov 5, 2007
just noticed, on my MBP 10.5 with 1920x1200 reso, it shows the garbled screen thing.
BUT if i first set the reso to 1680x1050, then connect VNSea, then change reso to
1920x1200 while connected, it works fine at the higher resolution... 
Nov 6, 2007
Yes, this issue happens to me with the built-in VNC server on Mac OS X 10.4.10 with extended desktop.
Nov 8, 2007
I'm using a 15" MBP with ext monitor, both screens set at 1440 x 900. All I get is the garbled screen (black 
background with lots of colored horizontal lines.)  I'm using Leopard screen sharing. btw. thanks for the 
development of this app - can't wait to get it to work properly!
Nov 8, 2007
Project Member #27
I have confirmed that any device context over 1024 HEIGHT does not display properly
The Horizontal extent goes to 1920.. NO prob..
But set the vertical extent over 1024 and BOOM!!!  Nothing displays
the device context is broken.. Bug in display drivers.

Nov 10, 2007
Project Member #28
Yep.. Figured this one out.
If the combined Width * Height > 2 MB then the crash happens.

I have added code in the .52 release that truncates the height to stop the garbage.
So you can view your screens but won't see the bottom part.

It appears that the iphone/touch can not have a device context > 2 MB pixels

Thinking about a workaround.

Nov 18, 2007
Project Member #29
Closing this defect as fixed because we now have a workaround, however imperfect. There may be no way to 
really fix this until contexts larger than 2 Mpixels are supported by GraphicsServices/UIKit. 
Status: Fixed
Nov 18, 2007
Project Member #30
(No comment was entered for this change.)
Status: Verified
Nov 18, 2007
Unfortunatelly the fix doesn't work for me. Maybe an idea: You could maybe implement 
hotkey push on logon so you could for instance set hotkey to disable extended 
desktop on PC/MAC or any other function. Connection would probably disconnect in 
this case but you could probably do quick auto reconnect. 

Thank you again for excellent application. 
Nov 19, 2007
I have one monitor at 1920x1200 and one monitor at 1680x1050 and it still crashes
VNSea, even with v0.6
Nov 21, 2007
Project Member #33
Yeah, seems the workaround wasn't. Reopening.
Status: Started
Nov 21, 2007
Project Member #34
(No comment was entered for this change.)
Labels: -Priority-High Priority-Critical
Dec 1, 2007
Mirror screens show black screen.

both are 800x600 @ 60Hz
Dec 10, 2007
#36 jerr0328
Tested with VNsea 0.6 on iPod Touch 1.1.2 and WinXP Home TightVNC Server 1.3.9
Setting a fixed rectangle for it worked (when it was small enough), but any larger or
increases either caused things like in comment 9 or a crash
Dec 17, 2007
Tested on VNsea 0.7
Have TightVNC server on Vista. Have 2 screens both set to 1280x1024. Comes up all
garbled. If i set TightVNC to only display the primary display works fine.

Dec 17, 2007
Yes, I am having this same problem on my dual monitor setup.
Dec 18, 2007
This problem appeared for me after upgrading to 0.5... where's the 0.4?
Dec 22, 2007
This was working for a while, but appears broken again with 0.6/0.7
Feb 9, 2008
With Version 0.81 the same problem appears. Doesn´t matter if tightVnc, RealVnc or
Ultra VNC is used. I use 4 displays,when i only activate one, it works fine. Maybe
there is another workaround?
Feb 9, 2008
That is strange, i deactivate all screens except the primary and it worked fine, than
i restart realvnc and activate my second wide screen display at 1650 x 1050px and
restart vnsea and it works!!! I disconnect again, restart it and it failed
again..Thats strange...i will retry it again. Is there no way tell the vnc server
only to serve for example only the primary vga adapter??? That should work.
Feb 21, 2008
Still having problem.
VNC Server: x11vnc v. 0.8.4 on Gentoo Linux
vnsea version 0.81
server configuration: 2 x (1280x1024) screens (2560x1024 desktop)
client configuration: firmware 1.1.3, ipod touch 16GB

client works fine connecting to 1280x800 UltraVNC on WinXP Home SP2
Mar 3, 2008
This problem occurs for me as well with my multi-display setup.

ipod touch 1.1.3
windows xp professional, 2 x 1280*1024
works when one of them is disabled.

having this issue fixed would be awesome.
Mar 7, 2008
I know it sounds like we are beating a dead horse here and perhapswe are expecting 
too much from the iPhone...who knows. Here is the problem I am experiencing:
Text appears to display just fine but when you have mixed text and graphics, the 
display will garble the graphic. See screenprints.

I want to be able to remote control my servers in event of an emergency and cannot 
access a regular computer. Hopefully, this can be worked out.

I am running VNSea 0.81 accessing TightVNC 1.3.9 on Windows XP Service Pack 2

I also want to run this on Vista but I am hearing there are issues with Vista and 
TightVNC. Anyone have any suggestions?
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Mar 8, 2008
I've attached a screenshot of my "garbledness". I've only tested on Vista Ultimate
because all of the computers i have run it....

VSsea 0.81
iPhone Firmware 1.1.3
Vista Ultimate
TightVNC Server
vnsea vista tightvnc iphone 113.png
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Mar 8, 2008
To add to my last comment (#46):

Also, changing resolution doesn't seem to help anything, my laptop runs at 1440x900
and i tried every possible setting below that and always had the same results.
My desktop does not use a wide screen monitor (it runs 1280x1024) and has the same
Mar 17, 2008
I've got the same problem.

* VNSEA 0.81
* ipod touch 32gb - 1.1.4
* winxp sp2
* VNC Server Enterprise Edition E4.2.5
* dual widescreen setup: twice 1680x1050
* ultramon v2.6.23.0

I've got a garbled screen when both monitors are in use, like the coloured lines one
user posted before. When I deactive my secondary screen, I'm able to control the

Really hope this can be fixed in a future version. If there's still development going
on for this program.

Apr 5, 2008
I tried with different kind of VNC serveur ( REALVNC ULTRAVNC... ) on my computer (
PC WINDOWS XP ) and I still have the same probleme.

Any news ?
Apr 25, 2008
I too was having the problem as stillness.into.flight with version 0.81 and TightVNC
1.3.9 on Vista Business and 1.1.4 of iPhone. Changing the pixel depth from 16 to 8
fixed it though. I have a 22" monitor running at 1680x1050. 

Thank you for this amazing program!
Apr 25, 2008

i feel pretty silly now because its simply a configuration option - but THANK YOU. it
freakin works. i can see everything clearly. that's freakin awesome.
Apr 26, 2008
No need to feel silly. There are some things that need to be explained and this 
happens to be one of them. The fact that it took this long for something so easily 
fixed is what is silly. I would also point out that you lose quality in the graphics 
when you drop down to 8 and you lose speed performance when you bump up to 32. 16 is 
not working and still needs to be fixed. IMHO
May 7, 2008
Is there any way to have TightVNC always start with "Sharing area: Primary Display" 
instead of full screen? That would work for me ;)
May 7, 2008
You can set the display as primary only under vnc server properties on the vnc host.
That ended up working for me. Too bad though , I'd love to use my dual monitors on
vnc. :)
May 8, 2008
yeah I tried that, works fine, but when I restart the VNC server its right back 
to "full screen" again- any way to permanently keep it at "primary display" ?
May 8, 2008
Ah solved it, added winvnc.exe to autorun then a batfile running "winvnc.exe -
May 13, 2008
I just discovered something. On my mac with leopard I had this problem. I also have dual monitors. Then I 
thought maybe the problem is not vnsea but leopard (leopard has built in vnc server). So instead I used vine 
server on port 5902 instead of 5900 and bingo! It works! I can only see one monitor but at least it's usable. 


Jun 2, 2008
Same problem on 24" iMac with dual display (1920x120 + 1280x720) using Leopard screen sharing. Works 
when external display is set to mirror the main one, but garbled when separate display are used.

Jul 10, 2008
can't wait for this to work.  wish my server didn't have dual monitors.

Jul 16, 2008
does anyone know what is going on with this problem?  seems like it is a bit of a
road block

Mar 10, 2009
Using UltraVNC the primary monitor is only displayed. This is a good workaround for
the time being
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