I moved my "Ubuntu 12.04.2 LTS" boot drive to a new computer.
The desktop login still looks okay, but if I connect via VNC, I get a blank screen instead of my Unity desktop.
syslog has some errors, that seem to start with this one
"x-session-manager: Gdk-WARNING: x-session-manager: Fatal IO error 11 (Resource temporarily unavailable) on X server :25.#012"
My VNC session is "25" deliberately, but I have tried other numbers.
"compiz: segfault at 3c ip b6113057 sp bfdaf810 error 4 in libcomposite.so[b6108000+21000]"
.xsession-errors has some error messages, like
(gnome-settings-daemon:4692): color-plugin-WARNING **: unable to get EDID for xrandr-default: unable to get EDID for output
I/O warning : failed to load external entity "/home/clarence/.compiz/session/10301235a14df254bb136120456075273800000046400036"
X Error of failed request: BadValue (integer parameter out of range for operation)
Major opcode of failed request: 109 (X_ChangeHosts)
Value in failed request: 0x5
I moved the disk from a desktop with an unsupported old NVidia card
model name : Intel(R) Pentium(R) 4 CPU 2.80GHz
01:00.0 VGA compatible controller: NVIDIA Corporation NV18GL [Quadro NVS 280 SD] (rev c1) (prog-if 00 [VGA controller])
to a Lenovo T61p laptop with model name : Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz
01:00.0 VGA compatible controller: NVIDIA Corporation G84M [Quadro FX 570M] (rev a1) (prog-if 00 [VGA controller])
I have tried with nouveau and NVidia drivers, using either "display" or the NVidia tool to configure for external display only, or dual.
It just occured to me that I haven't tried with the external dsiplay disconnected.
I have tried to follow various "reset unity" and "reset compiz" threads, to no avail.
Should I uninstall and reinstall a few packages?