For the past several months, my 27" iMac has been sporadically freezing and crashing with no discernible pattern (except that it happens at least once a day, usually more). Not sure what to do because I can't force a crash - it just happens without any noticeable patterns. Please help. I have collected the following facts about the lockup: Each time it freezes, Parallels 5 (latest version) is always running The freezing occurs while I'm working as well as while the iMac is idle (overnight). If the iMac is idle during the freeze, then it continues to run (I can hear it), but it will not turn the screen on or respond to mouse or keyboard input. If I am using the iMac during the freeze, the computer continues to run (I can hear it) but the screen is fully frozen, not responding to mouse or keyboard input. No warning, no beach ball. iMac runs fine (no errors) after restart, but USB Printers (all 3, see below) must be rechecked in Parallels USB options and put back online in Windows Printers & Faxes Just before freezes, the most common applications running are: Parallels Postbox (Mac) Safari or Chrome (Mac) AutoCAD 2007LT (Windows) Microsoft Word 2007 (Windows) Microsoft Excel 2007 (Windows) Adobe Acrobat Professional 9 (Windows) We have tried the following things to diagnose the problem: suspected it might be Safari: switched to Chrome, freezing continued had printer issues: spooler subsystem would crash, printers would disappear - followed manual directions on MS Knowledgebase, whitelisted spooler for DEP protection, enabled automatic spooler service restart on crash: problem seems fixed but freezing continued Here are the console logs from some of the crashes, in case they are useful: 01.25.10 - Crash around 10:14am 02.04.10 - Crash around 04:49pm 02.26.10 - Crash around 09:45am iMac Setup 27" iMac (late 2009) Processor: 2.66GHz quad-core Intel Core i5 RAM: 4GB Mac OSX 10.6.2 with latest software updates Parallels 5.0.9310.546799 Time Machine enabled Nightly incremental SuperDuper backups Parallels Setup Software Windows XP SP2 All Windows Updates installed AVG Pro antivirus (latest updates, no viruses) Video 256 MB 3D Acceleration Enabled Vertical Synchonization Enabled Hard Drive 64GB expanding disk Networking Shared Networking Sound Default Sound USB HP LaserJet 1022 (shared back to the Mac via networking) HP ScanJet 2200C IEEE-1284 Controller (parallel to USB connector for HP DesignJet Plotter) Processor/RAM 1 Processor 1536 MB RAM Settings Adaptive Hypervisor: Enabled Autocompress Enabled Tune Windows for Speed Enabled Optimize Performance for Virtual Machine Power consumption (Longer Battery Life) Time: Synchonize with Mac Security Settings: not enabled Sharing: Home Folder (access windows folder from Mac) (mount virtual disks to desktop) Shared Profile: Enabled (all) Shared Aplications (yes, smart select enabled, mac osx apps shared with windows Smart Mount: Enabled (all) Smart Guard (disabled) Undo disks (disabled) Crystal & Coherence (do not use dock area, show windows system tray icons) Gestures Enabled, Apple Remote Enabled