Black screen!

[my.ultravnc]

I'm connecting to remote PC, entering password and after that i can see only black screen!

how fix this problem?

[redge]

basic information ?
OS and vncviewer version ?
OS and winvnc version ?

latest is not an answer and would not be answered.
step by ste to reproduce ?
physical computer or/and virtual computer ?
vncviewer direct or trough ms remote desktop ?

[my.ultravnc]

on vncviewer - win xp sp3 pro in LAN behind Kerio win route. ports are forwarded. IP is static

on vncserver - win xp sp2 pro - direct connect to INTERNET with static IP

ultravnc version - 1.0.9.5 on both computers
both - physical PC

step by step:

1. run vncviewer
2. click "auto scaling", click "connect"
3. enter pass when asked
4. see black screen

user on remote PC can see how i\m moving mouse, cliking...

but i can't see remote screen

[redge]

unable to reproduce your issue, maybe related to SP2 ?

could you try this file
just replace winvnc and vncviewer at both side and let us if problem still exist
http://www.uvnc.eu/download/winvnc_dnstest.zip

what the screen size (1024x768 ? )and number colors (15, 16, 24, 32 bit)
if 15 or 24, switch the palette colors to 16 or 32 bit at vnc server.

[DaleStan]

We are routinely seeing this under the following circumstances:

Our "machines" are run by two or more computers, both behind a router. The router forwards incoming UltraVNC requests to the server computer. If we need to get to the workstation computer, we then create a second UltraVNC connection from the server to the workstation.

UltraVNC 1.0.9.5 installed everywhere.
Mirror driver installed on server and workstation, but not on remote machine (The remote machine also does not have a VNC Server.)
The server and workstation are both running XPSP3, x86.
/notoolbar and /fullscreen are both specified when connecting from the server to the workstation. (Testing suggests that either one of these switches is sufficient.)
For what it's worth, the server has no monitor, keyboard, or mouse.


Connections to the server (from a remote computer, running one of Win7SP1 x86, Win7SP1 x64, or XPSP3 x86) work fine. If we then connect from the server to the workstation, the server->workstation connection returns a black screen. The remote->server connection is still operating properly, as evidenced by:
- The presence of the server UVNC viewer system bar in the remote viewer (with the workstation's computer name and restore/minimize/close buttons)
- If not suppressed by /notoolbar, the UVNC toolbar displayed by the server viewer.
- Proper video response from various input commands, such as clicking the "Send ctrl-esc" button on the remote viewer.

In our testing, it is always the second (in this case, server->workstation) VNC connection that does not provide video. Even with both /notoolbar and /fullscreen, the remote->server connection works fine.

I looked at redge's zip file, but it does not contain any file that looks promising as a replacement for the VNC viewer. Was this intentional?

[Rudi De Vos]

What are you trying to do, don't understand the setup.

Connections to the server (from a remote computer, running one of Win7SP1 x86, Win7SP1 x64, or XPSP3 x86) work fine. If we then connect from the server to the workstation

1)PCA (viewer) connect to server (winvnc). OK
2) server connect to workstation
Do you run a viewer on the server already running winvnc to connect to another pc workstation running winvnc ?

[DaleStan]

Do you run a viewer on the server already running winvnc to connect to another pc workstation running winvnc ?

Yes. The server is simultaneously running both the winvnc service and the vncviewer.

[Rudi De Vos]

Should work if viewer is not in directx mode.

[DaleStan]

Assuming DirectX mode is controlled by the checkbox in the Connection Options dialog labeled "Directx (experimental)", neither viewer is in DirectX mode – neither box is checked.

[Rudi De Vos]

Is the viewer also black on "server" then you first need to check
the connection between server and workstation.

[DaleStan]

Connection from server to workstation is good. I moved a monitor to the server, and it displayed the workstation screen as expected. Remote computer sees everything on the server, except the display from the workstation.

It turns out display from the workstation is not always black; it's just unreliably updated. Requesting a screen refresh in either viewer will cause the workstation display to update, and obscuring the workstation display with something like an explorer window will sometimes trigger a partial update. Both are one-time updates.

Keyboard and mouse input moves correctly all the way from remote through server to workstation.

[Rudi De Vos]

I try again...

PC A viewer
server winvnc+viewer
workstation winvnc.

If you are in front of the server, is the viewer correct displaying the workstation.

[DaleStan]

If you are in front of the server, is the viewer correct displaying the workstation.

Yes.
It appears that there is nothing wrong with the server->workstation connection.

The issue, as far as I can tell, is the interaction between the vnc viewer and the winvnc service on the server. Updates displayed by the viewer on that computer are not regularly/reliably retransmitted by the winvnc service.

And again: This, for whatever reason, only happens if the server->workstation viewer is started with at least one of /fullscreen and /notoolbar.

[Rudi De Vos]

WHat are the polling options on the "server" for winvnc.

Try with following options...on, other off

[v] fullscreen polling
[v] systemhook
[v] low accuracy

[DaleStan]

I believe I pinned down the remaining mystery condition: The "Video Hook Driver" checkbox was checked. Unchecking that on the server (that is, the server PC) caused the issue to go away.

Specifically, I had:

Code: Select all

[poll]
TurboMode=0
PollUnderCursor=1
PollForeground=1
PollFullScreen=0
OnlyPollConsole=0
OnlyPollOnEvent=0
MaxCpu=100
EnableDriver=1
EnableHook=1
EnableVirtual=0
SingleWindow=0
SingleWindowName=

Changing to EnableDriver=0 made the issue go away.

Thanks for your help.

[stevebovy]

I have win xp 32 bit sp3 and I am trying to connect to a Linux machine centos

I keep getting periodic black screen flashes

very annoying and irritating I have the current version of the viewer installed

[Rudi De Vos]

If the server send a black screen from time to time, then the viewer also show the black screen,
Please check first with another viewer to findout if it's a ultravnc viewer only issue or a general viewer
thing.
Try with the viewer from tight ot realvnc.

[ProIT_Admin]

I had this similar problem on an x86 Windows XP VM and I rolled the version back from v1.2.1.1 to 1.0.5 and it worked fine.
I am not sure of the reason, but in my troubleshooting, I tried rolling back to the versions 1.1.9 and 1.0.8 without success before finding 1.0.5 worked.

[Rudi De Vos]

please try pre-release 1212