I'm trying to VNC into an OSX 10.4.11 box from Vista using RealVNC and TightVNC. I can connect successfully, but after a minute or so my VNC window freezes completely, while on the Mac the AppleVncServer process starts eating up huge amounts of RAM (100Mb +) and CPU (40-50%) - but the Mac doesn't freeze. When this happens no-one can VNC in anymore until the AppleVncServer process is restarted.

I have trawled through all the available options on the VNC clients I'm using and I don't see anything obvious that would cause this behaviour. I'd be grateful for any insights into this.


UPDATE: After more troubleshooting it seems this happens only when I to a copy on Vista. As soon as a copy operation is performed VNC freezes up. Note that copy paste inside VNC works fine....

  • Reflecting back on this, it should probably have been moved to superuser
    – Darko Z
    Jul 29, 2011 at 4:17

4 Answers 4


This is a known issue with clipboard incompatability.

For Example a TightVNC connection configuration file will contain disableclipboard=0. Change that value to 1 and your VNC server on the MAC side will not crash.

  • I confirmed Evan's answer - it's the clipboard thing. i'm trying winxp to macosx
    – user59553
    Nov 8, 2010 at 15:44

I've had similar problems in the past with RealVNC and TightVNC.

Have you tried UltraVNC yet? This solved the problem for us. Not sure why.

  • thanks i'll give it a go. also troubleshooted some more and updated question
    – Darko Z
    Jul 14, 2009 at 2:00
  • sorry mate, Ultra VNC wont even log on. According to UltraVNC no-one uses passwords longer than 8 characters
    – Darko Z
    Jul 14, 2009 at 2:07
  • 1
    Very strange. We're using UltraVNC with an 11 character password.
    – KPWINC
    Jul 14, 2009 at 2:30
  • +1 for UltraVNC, RealVNC and TightVNC sorely need improvements... Aug 15, 2009 at 1:06
  • +1. Switching to UltraVNC and turning off the clipboard option fixed this problem for me. UltraVNC looks way better than RealVNC too. Jun 28, 2011 at 21:48

I had exactly the same problem with Tiger except I was trying to remote in from a Windows XP machine. I tried a variety of different clients, all with exactly the same results.

In the end I just turned off the VNC server included with Mac OS X and installed Vine Server instead. Never had a problem with Vine Server, no matter which client I used on the Windows PC.


I should probably mention, when I upgraded to Leopard, I went back to using the included VNC server. It seems to be more stable.


Shot in the dark - As you are saying it is to do with file copy, possibly try running vnc viewer as administrator or disable UAC as it could be a permission issue.

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