We began experiencing failed vnc connections to the console display on servers that have been updated to EL 6.3. No such failures have occurred on similar connections to EL 6.2 servers. On the client machine a normal vncviewer display appears with the expected graphical login until the mouse pointer is moved within the boundaries of the vncviewer window. At this point the window closes and an error message appears in both a pop-up window and in the terminal window in which the session was initiated stating "read: Connection reset by peer (104)". On the server end, a core dump is generated and a abrt bug report is created. /var/log/messages ---------------------------------------------- Aug 14 11:00:30 jato2 abrt[11411]: File '/usr/bin/Xorg' seems to be deleted Aug 14 11:00:30 jato2 abrt[11411]: Saved core dump of pid 7892 (/usr/bin/Xorg) to /var/spool/abrt/ccpp-2012-08-14-11:00:30-7892 (42041344 bytes) Aug 14 11:00:30 jato2 abrtd: Directory 'ccpp-2012-08-14-11:00:30-7892' creation detected ---------------------------------------------- This bug has been reported in the CentOS bug tracker here: 0005824: tigervnc-server-module keep crashing http://bugs.centos.org/view.php?id=5824 However, this appears to be a bug upstream. The source RPM provided with CentOS is identical to that of upstream with no modifications. Also, there is an upstream bug reported that appears to have the same symptoms. I have added a comment to the upstream bug report (listed below) if anyone wishes to see the details. tigervnc-server-module crashes with dual screen setup https://bugzilla.redhat.com/show_bug.cgi?id=820443 We have verified that rebuilding the unmodified source RPM for tigervnc produces a tigervnc-server-module RPM that does not suffer from this bug. Removing the original tigervnc-server-module package and replacing it with the rebuilt one fixes the problem. I've duplicated the problem on 2 EL 6.3 x86_64 single-head display machines and have verified the fix. Tomorrow, I'll duplicate the problem on a dual-head x86_64 machine that currently still works after updating to EL 6.2 then confirm the the fix. ./Cal