vnc viewer display only little square of top left corner, other 90% area remains whole black

[kissson]

no modify of the picture, it is really it is.
viewer version 1.8.0.4 , this issue also occurs in the previous versions.

[RudiDeVos]

This is an edge case.
I can't repeat it between 2 windows server with UltraVNC server/viewer running

[Neustradamus]

@kissson: Can you add the UltraVNC Server ultravnc.ini files (important without password) and UltraVNC Viewer settings?

Can you add logs?

What is the OS of the Viewer machine and Server machine?

UltraVNC 1.8.0.4 in 2 sides?

[Neustradamus]

I had seen the same problem but I have no logs (not black but grey to all the screen).

I have requested an improvement to @RudiDeVos to have a better system log file for UltraVNC Server and to have a system log file for UltraVNC Viewer. All log files are very important to debug.

And @anarchocactus has done a good ticket too about logging!

• Enabled logging is not honored on start of UltraVNC Server #340

[RudiDeVos]

Only changes between 1.8.0.4 and 1.8.0.6 is unicode and folder file transfer, i don't expect this issue to be changed

[kissson]

I found that lot of my servers making the reverse connection are 1.2.2.4 toooooo old (I think it is the problem causing black area display), and the log I got in viewer 1.8 shows

DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-8kcdqbl ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-74b78tc ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-rpdhogu ( 10.8.0.2, 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-jp4ok7t ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 32
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-8g0cgnl ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-btablbs ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 32
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-oti0fbe ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 32
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "i3-w7-no2-pc ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 32
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "g1820-w7 ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 32
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-74b78tc ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
rdr::Exception (2): rdr::SystemException: read: Unknown error (10060)
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-74b78tc ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24
rdr::Exception (2): rdr::SystemException: read: Unknown error (10060)
DSMPlugin not enabled
RFB server supports protocol version 3.8
Connected to RFB server, using protocol version 3.8
No authentication needed
Desktop name "desktop-6aj7dgl ( 192.168.x.x ) - service mode "
Geometry 1920 x 1080 depth 24

that it still using old RFB 3.8 , is it currently RFB 5.x ??!
the main problem is it is hard for me to update a lot of server side to 1.8.x.x since the .ini path no longer the same in newer version, I am currently try to update all the server exe to 1.6.4.0 (the last version can have the ini in the same path to the exe) , by renaming the old 1.2.x.x 1.3.x.x 1.4.x.x exe to exe.old in file transfer and upload the 1.6.4.0 exe to the same path

---

server side 1.4.3.6 shows

Fri Apr 10 10:23:48 2026
vncClientUpdateThread::EnableUpdates : disable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncEncodeMgr::SetClientFormat : SetClientFormat called
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : no translation required
vncClientUpdateThread::EnableUpdates : enable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncClientUpdateThread::EnableUpdates : disable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncClientThread::run : ZRLE found 
vncClientThread::run : XZ found 
vncClientThread::run : Tight found
vncClientThread::run : compression level requested: 6
vncClientThread::run : Full-color cursor shape updates enabled
vncClientThread::run : PointerPos protocol extension enabled
vncClientThread::run : image quality level requested: 8
vncClientThread::run : XOR protocol extension enabled
vncClientThread::run : LastRect protocol extension enabled
vncClientThread::run : ServerState protocol extension enabled
vncClientThread::run : KeepAlive protocol extension enabled
vncClientThread::run : IdleTime protocol extension enabled
vncClientThread::run : FTProtocolVersion protocol extension enabled
vncClientThread::run : KeepAlive protocol extension enabled
vncClientThread::run : Extended clipboard protocol extension enabled
vncClientUpdateThread::EnableUpdates : enable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncEncoder::GetRemotePalette : remote palette data requested
Fri Apr 10 10:27:13 2026
desktopSelector::SelectHDESK : SelectHDESK to Default (dc) from dc
 --An existing connection was forcibly closed by the remote host.
vncClientThread::run : client disconnected : A.B.C.D (1)
vncClientUpdateThread::Kill : kill update thread
 --The specified module could not be found.
vncClientUpdateThread::run_undetached : stopping update thread
vncClientUpdateThread::~vncClientUpdateThread : update thread gone
vncServer::RemoveClient : removing authorised client
vncServer::RemoveClient : deleting desktop server
vncDesktop::~vncDesktop : ~vncDesktop 
vncDesktop::StopInitWindowthread : ~vncDesktop::Tell initwindowthread to close 
vncDesktop::InitWindow : OOOOOOOOOOOO called wm_quit
 --Thread does not have a clipboard open.
DesktopWndProc : WM_DESTROY
vncServer::KillAuthClients : KillAuthClients() done
 --The requested resource is in use.
vncDesktop::InitWindow : OOOOOOOOOOOO end dispatch
 --Invalid window handle.
vncDesktop::StopInitWindowthread : ~vncDesktop:: iniwindowthread proper closed 
Fri Apr 10 10:27:14 2026
vncDesktopThread::run_undetached : quitting desktop server thread
vncDesktopThread::run_undetached : quitting desktop server thread:SetBlockInputState
vncDesktopThread::run_undetached : quitting desktop server thread:ClearShiftKeys
vncDesktopThread::run_undetached : quitting desktop server thread:g_DesktopThread_running=false
vncDesktop::ShutdownInitWindowthread : ShutdownInitWindowthread 
desktopSelector::SelectHDESK : SelectHDESK to Default (dc) from dc
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktop::Shutdown : delete ((RGBPixelList) 
vncDesktopThread::run_undetached : quitting desktop server thread:m_desktop->Shutdown
vncDesktop::ShutdownInitWindowthread : ShutdownInitWindowthread 
desktopSelector::SelectHDESK : SelectHDESK to Default (dc) from dc
vncDesktop::~vncDesktop : ~vncDesktop Shutdown()
vncDesktop::~vncDesktop : ~vncDesktop m_lGridsList.clear
Fri Apr 10 10:27:15 2026
vncServer::RemoveClient : desktop deleted
vncServer::RemoveClient : RemoveClient() done
vncClientThread::run : PostAddNewClient II
vncClient::~vncClient : ~vncClient() executing...
vncClient::~vncClient : deleting socket
VSocket::Close : closing socket
vncServer::AutoConnectRetry : AutoConnectRetry(): started
vncServer::actualRetryThread : Attempting AutoReconnect....
 --The parameter is incorrect.
Fri Apr 10 10:27:30 2026
vncServer::AddClient : AddClient() started
vncClient::vncClient : vncClient() executing...
vncServer::AddClient : AddClient() done
vncServer::actualRetryThread : leaving reconnectThread....
vncClientThread::run : client connected : A.B.C.D (1)
 --The parameter is incorrect.
vncClientThread::InitSocket : DSMPlugin Pointer to socket OK
vncClientThread::InitVersion : Send protocolMsg
vncClientThread::InitVersion : Send_OK
Fri Apr 10 10:27:32 2026
vncClientThread::InitVersion : m_ms_logon set to falsevncClientThread::run : negotiated version
Entered InitAuthenticate
vncClientThread::InitAuthenticate : Leaving InitAuthenticate
vncDesktop::Init : initialising desktop handler
vncDesktopThread::run_undetached : Hook changed 1
 --The parameter is incorrect.
vncDesktopThread::run_undetached : Hook changed 2
vncDesktop::KillScreenSaver : KillScreenSaver...
vncDesktop::Startup : InitVideo driver Called
 --The requested resource is in use.
vncDesktop::Startup : Driver option disabled 
vncDesktop::InitBitmap : No driver used 
vncDesktop::InitBitmap : bitmap dimensions are 1920 x 1080
vncDesktop::InitBitmap : created memory bitmap
vncDesktop::InitBitmap : got bitmap format
vncDesktop::EnableOptimisedBlits : attempting to enable DIBsection blits
vncDesktop::EnableOptimisedBlits : enabled fast DIBsection blits OK
vncDesktop::SetPalette : no palette data for truecolour display
vncDesktop::StartInitWindowthread : StartInitWindowthread 
vncDesktop::StartInitWindowthread : StartInitWindowthread default desk
vncDesktop::InitWindow : InitWindow called
 --The parameter is incorrect.
vncDesktop::InitWindow : InitWindow:OpenInputdesktop OK
vncDesktop::InitWindow : InitWindow:SelectHDESK to Default (2dc) from dc
DesktopWndProc : wmcreate  
vncDesktop::InitWindow : OOOOOOOOOOOO load hookdll's
vncDesktop::InitWindow : OOOOOOOOOOOO start dispatch
 --The specified module could not be found.
vncDesktop::StartInitWindowthread : StartInitWindowthread started
vncBuffer::CheckBuffer : request local buffer[8294400]
vncBuffer::CheckBuffer : fast blits detected - using DIBsection buffer
vncBuffer::CheckBuffer : local buffer=8294400
vncDesktop::SethookMechanism : Sethook_restart_wanted hook=0 driver=0 
vncDesktop::SethookMechanism : Hookdll status changed 
vncEncodeMgr::SetEncoding : raw encoder requested
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : only 8, 16 or 32 bits supported remotely - 0 requested
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : no translation required
vncEncodeMgr::CheckBuffer : request client buffer[8294412]
vncServer::Authenticated : Authenticated() done
vncClientThread::run : authenticated connection
vncBuffer::CheckBuffer : request local buffer[8294400]
vncBuffer::CheckBuffer : fast blits detected - using DIBsection buffer
vncBuffer::CheckBuffer : local buffer=8294400
vncClientThread::run : sent pixel format to client
vncClientUpdateThread::Init : init update thread
vncClientUpdateThread::run_undetached : starting update thread
 --The parameter is incorrect.
vncClientUpdateThread::EnableUpdates : disable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncEncodeMgr::SetClientFormat : SetClientFormat called
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : no translation required
vncClientUpdateThread::EnableUpdates : enable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncClientUpdateThread::EnableUpdates : disable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncEncodeMgr::SetEncoding : Hextile encoder requested
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : only 8, 16 or 32 bits supported remotely - 0 requested
vncEncoder::SetTranslateFunction : settranslatefunction called
vncEncoder::SetTranslateFunction : no translation required
vncDesktopThread::run_undetached : Wait for viewer init 
vncEncodeMgr::CheckBuffer : request client buffer[8302640]
vncClientThread::run : XZ found 
vncClientThread::run : ZRLE found 
vncClientThread::run : Tight found
vncClientThread::run : compression level requested: 6
vncClientThread::run : Full-color cursor shape updates enabled
vncClientThread::run : PointerPos protocol extension enabled
vncClientThread::run : image quality level requested: 8
vncClientThread::run : XOR protocol extension enabled
vncClientThread::run : LastRect protocol extension enabled
vncClientThread::run : ServerState protocol extension enabled
vncClientThread::run : KeepAlive protocol extension enabled
vncClientThread::run : IdleTime protocol extension enabled
vncClientThread::run : FTProtocolVersion protocol extension enabled
vncClientThread::run : KeepAlive protocol extension enabled
vncClientThread::run : Extended clipboard protocol extension enabled
vncClientUpdateThread::EnableUpdates : enable update thread
vncClientUpdateThread::EnableUpdates : enable/disable synced
vncEncoder::GetRemotePalette : remote palette data requested
vncDesktopThread::run_undetached : Wait for viewer init 
Fri Apr 10 10:27:33 2026
vncDesktopThread::run_undetached : Hook changed 
vncDesktop::FastDetectChanges : ### PixelsGrid 0 created !
 --The requested resource is in use.
vncDesktop::FastDetectChanges : ### PixelsGrid 1 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 2 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 3 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 4 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 5 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 6 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 7 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 8 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 9 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 10 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 11 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 12 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 13 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 14 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 15 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 16 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 17 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 18 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 19 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 20 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 21 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 22 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 23 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 24 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 25 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 26 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 27 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 28 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 29 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 30 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 31 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 32 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 33 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 34 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 35 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 36 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 37 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 38 created !
vncDesktop::FastDetectChanges : ### PixelsGrid 39 created !

is it normal or not ?
the black area problem maybe mainly appears in 1.2.x.x server sometimes (old protocol)
thanks

[Neustradamus]

@kissson: I have updated your message with all informations here (needed for @RudiDeVos) and I have removed from the bad ticket ^^

It is important to update your UltraVNC version on your Servers (to latest 1.6.4.x) before to a perfect 1.8.x.

• https://uvnc.eu/download/1642/UltraVNC_1642_x86_Setup.exe
• https://uvnc.eu/download/1642/UltraVNC_1642_x64_Setup.exe
• https://uvnc.eu/download/1642/UltraVNC_1642.zip

The installer does an upgrade and a reboot is needed.
The 1.6.x installer duplicates the ultravnc.ini (and do not removed) to C:\ProgramData\UltraVNC\ultravnc.ini.

Important, there are a lot of improvements and fixes between 1.6.x and 1.8.x:
If you can test the UltraVNC Server 1.8.x and UltraVNC Viewer 1.8.x on 2 machines of your network (one Server and one Viewer machines), you will see the real result.
You can try on 2 VMs?

Warning, if you use rules, please look here:

• version 1.6.4.0 message Error #318 (comment)

The RFB protocol is detailled here, the last is RFB 3.8:

• https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst
• https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst#protocolversion

If manual, about the new place of ultravnc.ini, if you use "Service mode" (the best solution), the file must be copied in %ProgramData% to have:

• C:\ProgramData\UltraVNC\ultravnc.ini

[RudiDeVos]

Thank you for the details. UltraVNC Server 1.2.2.4 is very old — the current version is 1.8.x. A version mismatch of that magnitude between server and viewer can cause display problems including partial black screens.

[Neustradamus]

@kissson: At this time, can you try the 1.8.0.8 release build?

• https://uvnc.eu/download/1800/UltraVNC_1808_x64_Setup.exe
• https://uvnc.eu/download/1800/UltraVNC_1808_x86_Setup.exe
• https://uvnc.eu/download/1800/UltraVNC_1808.zip