Previous 1 2 Next 19 Replies Latest reply: Jan 3, 2013 5:47 AM by LBA78
Wilkyman76 Level 1 Level 1 (0 points)

I've seen a few messages on here and on other sites about people's MBP's running about 5 to 10degC hotter after installing Mountain Lion.


I've had Mountain Lion for a good 5 days and I've seen no improvement. I've fixed permissions using Onyx, I've reset the PRAM and the SMC and I've also gone through all of my apps to update any that do not run on Mountain Lion.


No improvement.


As I sit here now and type, my MBP is running at 66degC and the fan is at 3000rpm.....I then use smc control to ramp the fan up to 6000rpm.....the temperature drops to around 62degC.....I then set the fanspeed to default. About 2 minutes later, the temperature increases and the fan automatically ramps up again to around 3000rpm. Ive also updated Adobe Flash.


I only have Transmission and Safari open - that's it. Nothing else.


Does anybody have any idea how to resolve this issue or do I need to hold tight and wait for Apple to acknowledge it and issue a corrective patch? Or simply, is it that my machine is on it's deathbed? It worked okay with Lion!


I am almost convinced that Apple are upgrading these new OSX in a way so that we all have to keep going out and buying new MBP's - this isn't going to happen. I will downgrade back to Lion, and then Snow Leopard, if I have to. I will get my full money's worth with this laptop, and then I might consider going back to Windows.....


Any suggestions would be appreciated.



Macbook Pro, Mac OS X (10.5.8)
  • eudaldfromgi Level 1 Level 1 (0 points)

    The same problem for me, in my MacBook Air, late 2010. I'm thinking about dowgrading from Mountain Lion to Lion. A request, and a possible solution for this in my post:


  • ryancassin Level 1 Level 1 (0 points)

    I'm running into this exact same issue. Sometimes the laptop will get as hot as 75 degrees C and freeze. Only since upgrading to ML. SMC reset didn't seem to help.

  • putnik Level 3 Level 3 (780 points)

    Have a look in Activity Monitor and see which process is taking CPU.  Click on top of the CPU column, to sort in order of magntitude.


    If it is mdworker, this is Spotlight indexing, which can take some time on a new installation.


    Screen Shot 2012-08-03 at 18.31.09.png

  • Wilkyman76 Level 1 Level 1 (0 points)

    Thanks Putnik. Unfortunately, nothing to do with Spotlight indexing as I've had Mountain Lion for about 6 days now. It just generally runs about 5degC than Lion and about 10degC hotter than Snow Leopard.


    And also Safari 6.0 sometimes crashes!


    I am almost now convinced that Apple are upgrading these new OSX in a way so that we all have to keep going out and buying new MBP's.


    I hope that Apple sort this out with 10.8.1.....I hope that they're aware of this overheating issue, although it appears that only a small number of users have it.

  • Wilkyman76 Level 1 Level 1 (0 points)

    This is ridiculous....only doing some casual browsing and temperature now at 75degC and fan kicking in.....Apple really know how to mess things up!


    I keep an eye on Activity Monitor and a number of processes go above 10% at different times...finder, mds, safari, windowserver......


    If I even go into Facebook, Safari ramps up to about 60 or 70% CPU, temperature rises to mid 70degC and my fan kicks in. Surely, this isn't good for my MBP!


    I am really sorry I upgraded to Mountain Lion - I reckon it's going to kill my machine!


    I have an Apple LED Cinema Display and when the MBP is hooked up with that, it runs 10degC hotter. I've not even thought about using my Cinema Display with Mountain Lion installed.....the fan will probably constantly run at 6000rpm Until Apple sort this out, my Cinema Display is useless now!

  • putnik Level 3 Level 3 (780 points)

    I have put my documents on iCloud but, since the new iWork update, find CPU use in Web Process and Numbers gets high a short time after doing any editing.   You probably know already, the  iStat Pro widget on your Dashboard is good for monitoring your computer.

  • Alancito Level 6 Level 6 (11,075 points)

    Wilkyman76 wrote:


    I hope that Apple sort this out with 10.8.1.

    "...we might expect to see 10.8.1 appear in Software Update well before the end of August, which should take care of the biggest launch bugs." ...From this article:


    Timeline: when will Mountain Lion see its first patches?

    Wilkyman76 wrote:


    ...I hope that they're aware of this overheating issue...

    You can make sure they're aware by reporting it here:




  • davidvoy Level 1 Level 1 (5 points)

    I upgraded my 2007 Aluminum iMac  to Mountain Lion, and one of the issues i have noticed that i NEVER had issues with in over 6 years is  OVERHEATING and Shut Downs.


    I even  upgraged  the patch  10.8.1 and still have the issues with sound (Crackles) and  HEAT

  • davidvoy Level 1 Level 1 (5 points)

    I just downloaded an app called  smcFanControl  and used it to bump up my fan speeds internally.

    my iMac runs 99 degrees now instead of 149 degrees.  
    my GPU was 194 degrees now its 122 degrees.

  • Stephen Spark Level 4 Level 4 (2,415 points)

    I have Mountain Lion running perfectly fine on an early 2008 MacBook Pro, normal temps and fan speeds. Although I chose to do a clean install rather than an update. I found over time and running OS updates on every OS X release my system was getting sluggish and taking forever to boot up. After backing up and opting for a clean install of Mountain Lion my old laptop is running just as good as a new one.


    Even back in the day when I was running Windows system I found if you were able to run a major OS upgrade without a problem you were lucky. Pretty much every time an issue popped up a clean install gets rid of all the crap you have accumulated over time which may cause issues running an update. A little work backing up your files and wiping your system once in a while is well worth the time.

  • Wilkyman76 Level 1 Level 1 (0 points)

    I've read mixed comments as to whether to "upgrade" or "clean install".


    How did you transfer all your files back over again after you did the clean install? Some people are saying that if you use Migration Assistant, then all you're doing is transferring all the clutter back onto your computer again. They say the best way is to manually do it, or fresh install, but how do you go about doing that?



  • Wilkyman76 Level 1 Level 1 (0 points)

    smcFanControl is a neat app, but the fact of the matter is that your OSX shouldn't rely on an external developed application to stop it running so resource heavy and at a very high's ridiculous!


    I will wait for 5.8.1 to see any improvements. If none, I will be forced to clean install it to see what happens!

  • Stephen Spark Level 4 Level 4 (2,415 points)

    First step I take is to make a list of the Apps I have installed that I want in the new setup as well as any irreplaceable folder/files you do not want to lose. Pretty much everything you need is in your User folder but creating the full bootable image will create a copy of everything on your hard drive just incase. A full image with CCC or SuperDuper can also be used to get your system back to square one if things go bad. Time Machine is also a good source to recover data, but I would use one of the other programs so you'll have multiple backups I found it also works best if you use the exact same user name on the new system to prevent file permissions issues.


    Read for the important stuff. It is out dated but still applies in Lion. iCloud also makes short work out of this as well. On first boot ML asks for your Apple ID, if you are using iCloud syncing Contacts, Calendars/Reminders, Notes and Safari Bookmarks will automatically get restored. All I had to do was replace my email folders and preference files for the hard stuff. On top of that copying from the back up your Documents folder, the Music/iTunes folder is all that is needed for iTunes and Pictures/iPhoto Library restored my iPhoto pictures.


    Then go out onto the net and download fresh installs for any third party apps you may use. A quick Google search will generally find any data or other files you need to recover that may be hidden in the file system. It sounds tougher than it is and once you've done it it will be much quicker and easier down the road when you have to do it again. I'm sure I missed lot of info here but check and double check that you have all the data you want back on your new setup before wiping any of your back up drives, give it a few weeks before you commit the drives to backing up your new system.

  • Wilkyman76 Level 1 Level 1 (0 points)



    Thanks very much for that detailed response. I will have a go at it at the weekend.


    Still running hot....not much I can do about this, and judging by what I've read, 10.8.1 hasn't done anything to resolve this. Very shoddy!

Previous 1 2 Next