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VNC - Blank Screen

I'm having some trouble, which has completely caught me offguard. I have been for weeks now (since I enabled it) using VNC to access my Mini from my MBP, both outside my network and via LAN. The other day I do the usual and log on via the VNC command in the URL and nothing. I noticed the VNC screen was black, but the cursor was visible. Went to Activity Monitor and noticed VNC was no longer responding. I know I know "Google is your friend" in this situation, however everything I've found seems to either not compute with my situation or has no bearing on what is wrong with my mini.


I've double-checked my router, firewalls, and network connectionbut nothing seems to work. I even spent about 6hrs digging through terminal to see if anything is 'hanging' or not parsing correctly. I found many threads including the one below, however it's not what I'm looking for. I've also tried everything from rebooting to removing configuration files and starting over.


https://discussions.apple.com/thread/1912914?start=0&tstart=0



Who knows...I'm stuck and I need some help.

MacBook Pro, Mac OS X (10.6.8)

Posted on Jul 6, 2011 5:41 PM

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26 replies

Jul 7, 2011 4:30 AM in response to Torn-Barb

Have you changed the screen resolution? For example the number of colors to be displayed?


You say VNC, so I'm assuming the system you are coming from is not a Mac, as then I would expect you to say Screen Sharing.


Assuming a 3rd party VNC client, have you experimented using the free Vine Server as the VNC server on the Mac? This could be just an experiment to make sure you are not having networking issues (which is unlikely if you are making it to a blank screen), or using Vine Server may be a work around until you solve the Mac OS X screen sharing server issue.


Have you tried other VNC clients? Since I do not know if you are using a Windows, Linux, Mac, iOS device, other, I cannot make any suggestions, but it is worth exploring to see if that changes anything. NOTE: If you are using a Mac, then the best client is the Mac OS X Screen Sharing client: Finder -> Go -> Connect to server -> vnc://address.of.the.mac

Jul 7, 2011 7:06 AM in response to Torn-Barb

Let me clarify, I’m using ScreenSharing, and using it between my MBP and Mini.


@BDAqua – I’m not sure I follow, the video connection would be directly related to my monitor output, correct?


@BobHarris – I did not change the screen resolution, I was using ScreenSharing one minute, logged off that and did something else. Came back and did was is now current state: black screen.


I’ve tried third party VNC applications (the chicken) and it just tells me I need to allow access, which I have. I have double checked all ports/firewall/configuration settings to ensure I have not made a change by mistake. I probably have, or maybe this is a known issue? I have no idea.

Jul 7, 2011 7:43 AM in response to Torn-Barb

OK, since this is Mac to Mac, then built-in Mac OS X Screen Sharing is the best option. I only mentioned the other VNC clients and servers under the assumption you were using a mix of operating systems.


Obvious question. Have you tried reboot? Both MacBook Pro and Mac mini.


Next level would be finding the Screen Sharing preferences on both the MacBook Pro and the Mac mini, then trashing them.


In truth, my recollection of blank screens was associated with someone trying to access the server at a lower color depth than the full 32-bit color on the server. This was generally associated with using a 3rd party VNC client (which is where my screen resolution question came from). However, this does not seem to be your situation, so I'm not sure my question applies any more.

Jul 7, 2011 10:29 AM in response to Torn-Barb

@BobHarris – Yes I much rather utilize native software on OS X, which is why I’m frustrated. No worries about the confusion on operating systems, I should have clarified.


Yes I’ve rebooted the mini twice and the MBP three or four times over the course of a few days. When I get home I’ll trash the preferences and see what I can do.


Yeah you’re right black screens are due to screen resolution, however I didn’t change any preferences. This is really irritating me, and it could be something as small as a ‘checked box’. I’ll review when I get home to see if anything we mentioned works.


Thanks again for your help.....

Jul 8, 2011 4:38 PM in response to Torn-Barb

I found this interesting while getting the black screen on the MBP.....



From the Mini:


ps aux |grep VNC

User 2402 0.0 0.0 2711716 3716 ?? S 6:32PM 0:00.02 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Ma cOS/AppleVNCServer

root 2353 0.0 0.0 2444888 1760 ?? Ss 6:20PM 0:00.01 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Su pport/RFBRegisterMDNS

User 2408 0.0 0.0 2435116 524 s001 S+ 6:32PM 0:00.00 grep VNC

root 2404 0.0 0.0 2444608 840 ?? Ss 6:32PM 0:00.00 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Su pport/VNCPrivilegeProxy



From the MBP:


ps aux |grep VNC

User 123 0.0 0.6 2745792 24888 ?? S 5:40PM 0:13.36 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Ma cOS/AppleVNCServer

root 35 0.0 0.0 2436696 1752 ?? Ss 5:40PM 0:00.01 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Su pport/RFBRegisterMDNS

User 672 0.0 0.0 2426972 360 s000 R+ 6:34PM 0:00.00 grep VNC



I also found this thread from MacRumors (http://forums.macrumors.com/showthread.php?t=441030), however; I don't see NetAuthAgent running on either machine.


Another thread on Apple Discussions is this: https://discussions.apple.com/thread/2289704?start=0&tstart=0 And it equals nothing.

Jul 8, 2011 5:57 PM in response to Torn-Barb

I have similar processes running on my MacBook and my Mac mini


35 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Su pport/RFBRegisterMDNS

83 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Su pport/VNCPrivilegeProxy

95 /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Ma cOS/AppleVNCServer


I'm thinking the RFBRegisterMDNS is responsible for advertising your Screen Sharing server over Bonjour (aka Zeroconf, aka Multicast DNS, aka mDNS).


I'm thinking the VNCPrivilegeProxy is related to the System Preferences -> Sharing -> Screen Sharing -> Computer Settings -> VNC viewers may control screen with password: xxxxxxxxxx. When I do a 'strings' command against the VNCPrivilegedProxy executable it mentions /Library/Preferences/com.apple.VNCSettings.txt, and when I Google that com.apple.VNCSettings.txt, I found references to setting the VNC password.


Basically I think you have the correct processes running, and the RFBRegisterMDNS and VNCPrivilegeProxy processes should only be involved in the initial connection and have nothing to do with displaying the screen.


That leaves AppleVNCServer which as the process responsible for exporting the screen, and most likely the one sending your an empty screen (as I would expect, except that I also expect it to send you a nice copy of you screen and not a blank screen :-) ).


You want to look at the Mac mini console logs.


/var/log/secure.log

/var/log/system.log

/var/log/windowserver.log


for starters. See if there are any VNC related entries. You can also use the Applications -> Utilities -> Console app to look at the logs.


NOTE: When looking at logs, check the time stamps, as you do not want to be looking at old entries. You want to attempt to make a connection from your MacBook Pro to your Mac mini and then check the Mac mini logs, checking the time stamps to make sure VNC related entries, or any entries around the time of your attempt have relevance.


With respect to preferences relevant to the server, these may be what you want to look at and maybe trash (or at least move to see if they change anything)


/Library/Preferences/com.apple.RemoteManagement.plist

/Library/Preferences/com.apple.VNCSettings.txt

/Library/Preferences/com.apple.ARDAgent.plist


If you do move (or delete) these plists, you will need to use System Preferences -> Sharing -> Screen Sharing to enable the relevant Screen Sharing preferences again. Set the minimum needed and then work you way up to move involved settings.

I would also stick with Sharing -> "Screen Sharing", and ignore Sharing -> "Remote Management"

Jul 8, 2011 6:03 PM in response to Torn-Barb

Not responding, might indicate Screen Sharing was wedged. Possibily waiting for a network reply, or some other system service to return.


In Activity Monitor, you can select Screen Sharing, and then click on Sample Process. This might tell you want Screen Sharing is doing internally. Then again, it might just be a bunch of jibberish.


If you have another (3rd) system you can try connecting to the Mac mini (even if it is friend), you could maybe isolate if the problem is coming from the MacBook Pro Screen Sharing client or the Mac mini Screen Sharing server.

Jul 8, 2011 6:22 PM in response to BobHarris

@BDAqua - Tried that, no bueno...



Well Mr. BobHarris, I did network security for 10yrs, and I guess being out of the game for a while has made me slack off a bit.... During my review of my logs via terminal I noticed that the Chinese and Russians have taken quite the interest in my machine, aka brute forcing my machine. Need to keep up with that.....


Anyhow, I tried your suggestions, no go. However the last suggestion of Sharing via a third computer not in the mix was successful from my wife's MBP.


So it appears we have an issue with the MBP, not the Mini.

Jul 8, 2011 6:44 PM in response to Torn-Barb

When trying to Share.....


System Log from MBP:


Jul 8 20:33:48 User com.apple.launchd[1] (com.apple.RFBEventHelper[1400]): Exited with exit code: 1

Jul 8 20:33:48 User com.apple.launchd[1] (com.apple.RFBEventHelper): Throttling respawn: Will start in 10 seconds

Jul 8 20:33:58 User com.apple.launchd[1] (com.apple.RFBEventHelper[1401]): posix_spawn("/System/Library/CoreServices/RFBEventHelper.bundle/Contents/MacOS/ RFBEventHelperd", ...): No such file or directory

Jul 8 20:33:58 User com.apple.launchd[1] (com.apple.RFBEventHelper[1401]): Exited with exit code: 1


System Log from Mini:


Jul 8 20:32:20 User Safari[2308]: Periodic CFURLCache Insert stats (iters: 379) - Tx time:0.106725, # of Inserts: 2, # of bytes written: 57956, Did shrink: NO, Size of cache-file: 175968256, Num of Failures: 0


I realize the Mini log is indicating Safari issue, but it's the only log within the time frame of me attempting the Sharing.


Good thing is on the Mini secure log I get the following:


Jul 8 20:32:59 User /System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Ma cOS/AppleVNCServer[2579]: Authentication: SUCCEEDED :: User Name: User :: Viewer Address: 10.X.X.X :: Type: DH

VNC - Blank Screen

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