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Welcome to Techsurvivors => Tech => Topic started by: Johanbgoot on June 06, 2014, 06:22:15 AM

Title: Suddenly my iMac freezes
Post by: Johanbgoot on June 06, 2014, 06:22:15 AM

I have a 2008 24inch iMac running 10.6.8. It has a 2.8 Ghz Core 2 duo processor and 4 GB ram ( maximum). Of a 320 GB hard drive, I am using 49.75 GB. About 2 weeks ago it began to just freeze without any reason.  I have run Techtool Pro and it passed all the tests.  I have used Onyx and DiskWarrior.  It will run all day and then without warning freeze. I have to do a cold start and it will run fine for a while and then freeze again.  BTW, I have not downloaded any software recently, nor updates. Does any one have any ideas/suggestions to resolve this?

Thanks,  Johan

Title: Suddenly my iMac freezes
Post by: jchuzi on June 06, 2014, 09:32:17 AM

Do you have any anti-virus software? Sometimes that's the culprit.

Other thoughts:

Reset SMC by shutting down completely, unplugging the computer for about 15 seconds, and then restarting.
Reset PRAM.
Did you use TechTool Pro to run a surface scan? You said that you did all tests but that one might be critical.

Title: Suddenly my iMac freezes
Post by: Johanbgoot on June 06, 2014, 10:30:09 AM

Every test including the surface scan passed in Techtool Pro.  I will try resetting things as suggested,thanks, Johan

Title: Suddenly my iMac freezes
Post by: jchuzi on June 06, 2014, 01:32:42 PM

This may be a long shot but I'll mention it: If the internal backup battery is weak, you can have weird symptoms. In my case, the computer would not wake from sleep and my only recourse was to do a forced shutdown by holding the power button. Then, it would restart normally. Replacing the battery cured it.

The battery is not user-replaceable in the iMac but you can run a simple test to see if it's weak. Disconnect the computer from the Internet (so you don't have an automatic adjustment to date and time) and shut down overnight. When you restart, see if the date and time are wrong. If so, the battery needs to be replaced.

Title: Suddenly my iMac freezes
Post by: iGuy on June 06, 2014, 04:16:56 PM

I have the same computer.  I have Micromats Checkmate software installed an it shows that my computer doesn't have a internal battery.  

This may not mean anything but a few months ago the original HD in mine went bad an had to replace it.  A Hard drive in beginning stages of failure could cause freeze ups.  The surface scan passing eliminates the hard drive I guess.

Title: Suddenly my iMac freezes
Post by: jchuzi on June 06, 2014, 06:42:00 PM

QUOTE(iGuy @ Jun 6 2014, 05:16 PM) <{POST_SNAPBACK}>

I have the same computer.  I have Micromats Checkmate software installed an it shows that my computer doesn't have a internal battery.

I also have Checkmate installed and it, too, shows that I don't have a battery. BUT I DO (and so does your iMac)! I believe that Checkmate refers to the rechargeable battery in a laptop, not the internal backup battery.

Johan,

I want to make sure that we're on the same page (and I should have asked this earlier): What exactly do you mean by a "freeze"? I interpret this to mean that the entire computer becomes unresponsive and you have to hold the power button to force a restart. Is this what's happening?

Or, is one program freezing and you have to force-quit it? If so, which program? If that's the case, you may be running out of RAM, particularly with memory-intensive apps like Photoshop. 4GB may not be enough.

Title: Suddenly my iMac freezes
Post by: Paddy on June 07, 2014, 08:51:01 AM

Johan, you should take a look at the system logs to see if there is an event preceding the freeze that might point to the culprit. You can look in the Crash logs in Console to see if there is anything there (likely not, as they're about single applications) and otherwise, if you've had a recent freeze and can remember the time it happened, look in the Console->system log queries->All messages to see if you can see anything just before you restarted.

Sometimes with a hard freeze you won't see very much of anything in the Console - but making careful note of what you were running or doing can sometimes isolate a cause or suspect.

Title: Suddenly my iMac freezes
Post by: Johanbgoot on June 07, 2014, 11:01:43 AM

QUOTE(jchuzi @ Jun 6 2014, 07:42 PM) <{POST_SNAPBACK}>

QUOTE(iGuy @ Jun 6 2014, 05:16 PM) <{POST_SNAPBACK}>

I have the same computer.  I have Micromats Checkmate software installed an it shows that my computer doesn't have a internal battery.

I also have Checkmate installed and it, too, shows that I don't have a battery. BUT I DO (and so does your iMac)! I believe that Checkmate refers to the rechargeable battery in a laptop, not the internal backup battery.

Johan,

I want to make sure that we're on the same page (and I should have asked this earlier): What exactly do you mean by a "freeze"? I interpret this to mean that the entire computer becomes unresponsive and you have to hold the power button to force a restart. Is this what's happening?

Or, is one program freezing and you have to force-quit it? If so, which program? If that's the case, you may be running out of RAM, particularly with memory-intensive apps like Photoshop. 4GB may not be enough.

It happens when I'm on the internet, usually watching YouTube. The pointer will move, but I get the spinning ball.  I can't force quit so I have to do a cold restart. If it happens again, I will note the time and look at the logs and report what I find.

Title: Suddenly my iMac freezes
Post by: Xairbusdriver on June 07, 2014, 01:19:04 PM

So, this is not your iMac freezing, it's just Safari? If this is not true, ignore the following questions.

1. Have you tried "Force Quit..." under the Apple Menu?
2. Under the "Preferences->Privacy" tab, how many websites is noted as storing cookies and data?
3. Have you tried running with Caches DIS-abled (you'll need to have Safari's Debug menu activated)?
4. How many and what Extensions do you have installed for Safari?
5. How many and what apps do you have running when this happens?

Title: Suddenly my iMac freezes
Post by: jchuzi on June 07, 2014, 01:49:43 PM

To add to Jim's reply:

If you can't access the Apple menu to force quit, try pressing Command-Option-esc.

Title: Suddenly my iMac freezes
Post by: Paddy on June 07, 2014, 04:34:26 PM

To add to both Jim's and Jon's suggestions, if either of those don't work, then you could try quitting Safari in Activity Monitor. I'd set it going (so it's already running when bad things happen) and then see if you can use it. Of course, if you're forced to reboot to get anything to happen, all bets are off - and I suspect this may be the case.

Title: Suddenly my iMac freezes
Post by: Johanbgoot on June 13, 2014, 02:01:04 PM

I did the internal battery test and there was no problem.  I had been using Opera as my default browser, but as suggested I tried Safari again, it is very slow and unwieldy.  Tried Chrome, no problems.  Then I received an update email for Firefox June 10 and downloaded it. It is fast and so far no problems.  Then today I tried Opera again and the imac froze.  I have concluded that it was the problem so I have uninstalled it; thanks everyone for you input, Johan