Well, my brand new (refurb) iMac 27”, i7, 16GB RAM, 1TB HDD (see Blown Away) is experiencing some frustrating problem that I cannot figure out. For what appears to be no reason at all, it will freeze up totally. No keyboard, mouse or Magic Trackpad actions will accomplish anything. The only button that works is the power button. When the iMac indiscriminately freezes, I hold the power button until it turns off. Then I can turn it back on again. This all started about 2 weeks ago. I can be browsing in Safari, reading Mail, adjusting System Preferences or doing nothing at all and it will freeze. It will freeze minutes after waking from sleep or hours or days. It will freeze after a warm boot and after a cold boot in minutes, hours or days; it freezes at a time of it’s choosing. It will freeze if there are open applications in the Dock or no open applications in the Dock. The only thing I can see as a pattern (almost) is that I haven’t noticed that it freezes while music is playing in iTunes. The other day I was listening to music for a few hours and it never froze up. Then I paused the music, went outside to load the wood burner and came back in about 4 minutes later to find the iMac frozen again. Every time it freezes and I boot it up again I check the Console. At first I saw several applications with problems and I fixed them by uninstalling them or searching the problem on Google and finding the solution. But still the freezing continues. Those issues were actually dated a few weeks prior to the beginning of the problem. One problem I had was that my WD MyBook HDD which I use for Time Machine was going bad and had crashed my iMac once. I had to wipe the drive and use Disk Utility to repair it. That worked for a week or so and then the drive crashed permanently to where I couldn’t repair it at all or even SpinRite it with an IBM PC. When it crashed for the last time I was in the middle of all the freezes and trying numerous things to fix it. So I was worried a little that I was without a backup and having troubles. I had ordered another drive from OWC and that came in and I got it running and backed up again successfully with Time Machine. In the Console, every time it freezes, I look at the time stamp to see what was going on. But I never find anything faulting except a Kernel panic which reads “npvhash=4095.” A Google search only turned up something about corrupt fonts in the Font Book. So I went there and found a few duplicate fonts and repaired them, but that didn’t solve the freezing problem. Every application that was logged around freeze time, I checked out and stopped the next time to isolate the issue but haven’t been successful. The first time I found it frozen was a day that I was downloading a video podcast in iTunes which was about 400MB or so. I left it downloading and set the display to sleep after 1 minute and the computer to sleep after 3 hours which I figured would be enough time to download as my connection speed is a bit slow. Then I left for work. When I returned home, the computer was still on and not asleep and completely frozen. Another thing I keep seeing in Console are messages that read “Firewall Stealth Mode connection attempt to TCP (or UDP) 192.168.0.194: (various port numbers) from 192.168.0.1: (various port numbers). Now .0.194 is the iMac and .0.1 is the router. Sometimes the sending IP is a public IP. (My AEBS is bridged to a Cradlepoint MBR-259 router which is then connected to a Sprint MiFi device for Internet service.) Below is a list of things I have gone through to try and solve the problem but so far none have worked. Disk Utility: Verify Disk Permissions, Repair Disk Permissions, multiple times Disk Utility: Verify Disk and it showed to be just fine Have SMARTReporter for HDD and it always reports that it is fine (though I never trust SMART as it doesn’t really work that well) Disabled GeekTool, then uninstalled GeekTool Repaired Font Book fonts Uninstalled Sierra Wireless Watcher (from the days when I had an AT&T air card) Reset PRAM & SMC Removed WD Drive Manager as it was one thing listed in Console that had an issue Used the app TrashMe to remove all third party apps and preferences that I was no longer using Turned off the OS/X Stealth Mode Turned off the OS/X Firewall All software and firmware updates have been checked and applied for OS/X, AEBS, Cradlepoint MBR-259 router and Sprint MiFi. Restarted all routers Apple hardware diagnostic utility (reboot computer while holding letter G or H, I forget which one now) and running the test showed all hardware to be working fine Ran Remember RAM tester and all 16GB OWC RAM checked out fine Uninstalled Adobe Flash Uninstalled Adobe Updater Turned off Bluetooth Used Onyx to:check SMART status, Structure of volume, Preferences, Permissions, Delete the caches of Boot, Kernel, International Preferences, QuickTime components, Other components, and nearly all of the things listed under Cleaning Created a new user account and within 2 minutes of using that one iMac froze up Backed up entire drive with Time Machine, inserted OS/X disc and rebooted, erased entire iMac HDD and reinstalled OS/X and then migrated apps, account info etc... from Time Machine and applied all Software Updates to OS/X bringing it back to 10.6.6 and computer still freezes Computer is plugged into an APC UPS unit About the only thing that I can find that is consistent, as I had already mentioned, was the console message npvhash=4095 and that so far it seems to not freeze while playing music in iTunes. Now before I go and drive an hour in one direction to get to my nearest Apple Store and drop this off to them to figure out, I call upon the vast and knowledgeable members and resources of MacRumors to assist me in anything that I may have not done to figure this out.