Imac crashing

Hi all, I have a 20" Imac and just lately it has started to crash. while I am working the screen just goes white and I have to restart the computer.

I have heard of the white screen when the machine is booting up but nothing about it when it is running!

anyone got any suggestions

Cheers

Open a new Finder window, then select Applications --> Utilities --> Console
double click to open, then on the left select LOG FILES --> System Log.

Now that you know how to do that, the next time it occurs you can look at the log once you reboot and see what it says. You can copy the last lines and post here.

Also please put all your machine details in your profile (Apple icon at top left --> About This Mac) so we can see your OS version, memory...and by the way how big is your hard drive and how much empty space does it have?

You can run Utilities --> Activity Monitor to see if you are running out of memory. You can download the nice iStat widget which will tell you similar stuff but also about temperatures inside the machine.

Great, Thank you Head Unit.

Here we go, my machine crashed again but this time it was with a black screen. and I have done what you said Head unit. my machine has 1.6G of memory remaining.


Mar 21 21:09:06 jennifer-grays-imac loginwindow[39]: loginwindow SleepWakeCallback will power on, Currenttime:3/21/2011 9:09:06.003 PM - Waketime:3/21/2011 9:09:06.000 PM = Deltatime:0.002823889
Mar 21 21:09:13 jennifer-grays-imac configd[14]: Sleep: Success - AC - Idle Sleep
Mar 21 21:09:13 jennifer-grays-imac configd[14]: Wake: Success - AC - EHC1
Mar 21 21:09:13 jennifer-grays-imac configd[14]: Hibernate Statistics
Mar 21 21:09:14 jennifer-grays-imac configd[14]: PMConnection AirPort configd plug-in com.apple.powermanagement.applicationresponse.slowresponse 8352 ms
Mar 21 21:09:14 jennifer-grays-imac configd[14]: PMConnection IPConfiguration com.apple.powermanagement.applicationresponse.slowresponse 8357 ms
Mar 21 21:09:14 jennifer-grays-imac configd[14]: network configuration changed.
Mar 21 21:09:23: --- last message repeated 1 time ---
Mar 21 21:09:23 jennifer-grays-imac Safari[15322]: Periodic CFURLCache Insert stats (iters: 558) - Tx time:0.061795, # of Inserts: 2, # of bytes written: 65907, Did shrink: NO, Size of cache-file: 181870592, Num of Failures: 0
Mar 21 21:09:34 jennifer-grays-imac ntpd[27]: time reset +0.495535 s
Mar 21 21:09:38 jennifer-grays-imac loginwindow[39]: no spins reported for this wake
Mar 21 21:11:00 jennifer-grays-imac Safari[15322]: INSERT-HANG-DETECTED: Tx time:6.074120, # of Inserts: 0, # of bytes written: 0, Did shrink: YES
Mar 21 21:18:43 localhost com.apple.launchd[1]: *** launchd[1] has started up. ***
Mar 21 21:18:49 localhost DirectoryService[11]: Improper shutdown detected
Mar 21 21:18:50 localhost blued[16]: Apple Bluetooth daemon started
Mar 21 21:18:58 localhost mDNSResponder[18]: mDNSResponder mDNSResponder-258.14 (Nov 18 2010 14:18:32) starting
Mar 21 21:18:59 localhost configd[14]: bootp_session_transmit: bpf_write(en1) failed: Network is down (50)
Mar 21 21:18:59 localhost configd[14]: DHCP en1: INIT-REBOOT transmit failed
Mar 21 21:18:59 localhost configd[14]: network configuration changed.
Mar 21 21:18:59 jennifer-grays-imac configd[14]: setting hostname to "jennifer-grays-imac.local"
Mar 21 21:18:59 jennifer-grays-imac configd[14]: network configuration changed.
Mar 21 21:19:05: --- last message repeated 1 time ---
Mar 21 21:19:05 jennifer-grays-imac bootlog[54]: BOOT_TIME: 1300706322 0
Mar 21 21:19:05 jennifer-grays-imac /System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow[43]: Login Window Application Started
Mar 21 21:19:05 jennifer-grays-imac fseventsd[47]: event logs in /.fseventsd out of sync with volume. destroying old logs. (1669899 23 1670305)
Mar 21 21:19:05 jennifer-grays-imac com.apple.usbmuxd[36]: usbmuxd-207 built for iTunesTenOne on Oct 19 2010 at 13:50:35, running 64 bit
Mar 21 21:19:05 jennifer-grays-imac fseventsd[47]: log dir: /.fseventsd getting new uuid: 8B9EDE9E-1419-49EF-B10E-CDA4BA72AE20
Mar 21 21:19:06 jennifer-grays-imac com.apple.SystemStarter[37]: Starting HP IO Monitor
Mar 21 21:19:06 jennifer-grays-imac com.apple.SystemStarter[37]: Starting HP Trap Monitor
Mar 21 21:19:06 jennifer-grays-imac mds[42]: sandbox cache error: database is locked
Mar 21 21:19:08 jennifer-grays-imac configd[14]: network configuration changed.
Mar 21 21:19:12 jennifer-grays-imac loginwindow[43]: Login Window Started Security Agent
Mar 21 21:19:12 jennifer-grays-imac loginwindow[43]: Login Window - Returned from Security Agent
Mar 21 21:19:12 jennifer-grays-imac loginwindow[43]: USER_PROCESS: 43 console
Mar 21 21:19:13 jennifer-grays-imac com.apple.UserEventAgent-LoginWindow[105]: ALF error: cannot find useragent 1102
Mar 21 21:19:13 jennifer-grays-imac com.apple.UserEventAgent-LoginWindow[105]: plugin.UserEventAgentFactory: called with typeID=FC86416D-6164-2070-726F-70735C216EC0
Mar 21 21:19:13 jennifer-grays-imac com.apple.launchd.peruser.501[112] (com.apple.ReportCrash): Falling back to default Mach exception handler. Could not find: com.apple.ReportCrash.Self
Mar 21 21:19:14 jennifer-grays-imac fseventsd[47]: check_vol_last_mod_time:XXX failed to get mount time (25; &mount_time == 0x10047f8b8)
Mar 21 21:19:14 jennifer-grays-imac fseventsd[47]: log dir: /Volumes/NIKON D90/.fseventsd getting new uuid: 345C155F-B028-4EB8-9930-D4D155154761
Mar 21 21:19:18 jennifer-grays-imac com.apple.launchd.peruser.501[112] (com.apple.Kerberos.renew.plist[143]): Exited with exit code: 1


Hope you can see something in there

Cheers Dale