Mac Mini (OSX6) freezes on boot if USB cable to KVM connected

Question

I have a Mac Mini (OS X 10.6.8) that has started freezing with a solid grey screen on boot up (i.e., no Apple logo, no spinning wheel). The work around is relatively easy: all I need to do is disconnect the USB cable running to my ATEN KVM CS1768 switch, power down, power up and then reconnect the USB cable once the Mac desktop is loaded. While this just happened three times in a row, it doesn't happen all the time. The first time it happened last summer I spent an hour on the phone with Mac support (the computer was still under warranty at that point) and the very last suggestion they made was to disconnect the USB cables before attempting to reboot. (I don't recall precisely if the problem occured when my USB peripherals-- a Mac USB keyboard and mouse-- were directly connected to the Mini rather than being routed through the KVM switch, but I *think* it did.)
If anyone has a quick answer or can point me to a prior discussion of this same (or a related) issue, I would be most grateful

Answer 1

Hi,
Thanks for the response. I've been using Macs for a little over four years now but this is only the first time I have gone to the system logs (or any of the other logs available from the consolute utility).
The system log appears to be completely unhelpful. I got up this morning sometime after 6:00 a.m. and posted my first report (see above) at 6:48 a.m. (I don't have a record of the exact times of the boot up freezes.)
Following are the *entire* contents ot the system log covering this period:
Nov 19 01:12:15 WHW-Mac-Mini loginwindow[40]: loginwindow SleepWakeCallback WILL sleep
Nov 19 06:26:35 WHW-Mac-Mini loginwindow[40]: loginwindow SleepWakeCallback will power on, Currenttime:11/19/2012 6:26:35.019 AM - Waketime:11/19/2012 6:26:33.980 AM = Deltatime:1.038853049
Nov 19 06:27:05 WHW-Mac-Mini loginwindow[40]: no spins reported for this wake
Nov 19 07:35:13 WHW-Mac-Mini login[17714]: USER_PROCESS: 17714 ttys000
I assume that one of the two successful reboots that I did during this period was probably at 6:27.
The "all messages" log has some additional information from this time frame that may be  useful:
11/19/12 6:26:35 AM
kernel
Wake reason =
11/19/12 6:26:35 AM
kernel
System Wake
11/19/12 6:26:35 AM
kernel
Previous Sleep Cause: 5
11/19/12 6:26:35 AM
kernel
EIR is supported.
11/19/12 6:26:35 AM
kernel
SSP is supported.
11/19/12 6:26:37 AM
kernel
AppleBCM5701Ethernet:   
0   
1 BJP firmware wakeup: service connect
11/19/12 6:26:37 AM
kernel
AppleBCM5701::selectMedium - autoselect, any duplex, flow control allowed
11/19/12 6:26:37 AM
kernel
Ethernet [AppleBCM5701Ethernet]: Link down on en0
11/19/12 6:26:38 AM
kernel
Ethernet [AppleBCM5701Ethernet]: Link up on en0, 1-Gigabit, Full-duplex, Symmetric flow-control, Debug [79ed,0f00,0de1,0300,c5e1,3c00]
11/19/12 6:26:39 AM
ntpd[28]
bind() fd 25, family 30, port 123, scope 4, addr fe80::c62c:3ff:fe1f:4f7, in6_is_addr_multicast=0 flags=0x11 fails: Can't assign requested address
11/19/12 6:26:39 AM
ntpd[28]
unable to create socket on en0 (17) for fe80::c62c:3ff:fe1f:4f7#123
11/19/12 6:26:40 AM
configd[15]
network configuration changed.
11/19/12 6:26:43 AM
/System/Library/CoreServices/RemoteManagement/AppleVNCServer.bundle/Contents/Mac OS/AppleVNCServer[140]
Authentication: FAILED :: User Name: N/A :: Viewer Address: 37.130.232.1 :: Type: VNC DES
Following this there were quite a few unsuccessful attempts to connect with my VNC server and little else that seemed noteworthy. Nothing that referenced anything to do with USB or USB peripherals.
And, of course, when I rebooted just now (in the hopes of getting a report from all of the logs corresponding to the exact time of the reboot), my Mini started just fine with no freeze up.