9 Replies Latest reply: Jul 18, 2010 10:38 AM by babowa
27imac Level 1 Level 1 (5 points)
When the Mac boots up, right after the Apple logo is gone and right before the blue screen shows there is a strange "twitch" or splotch on the screen of gray. The best way I can describe it is a very quick gray "snowy" image and then it goes to the blue screen. I never used to have that until a few days ago. My Mac is still under warranty. What should I do?

27-inch iMac, Mac OS X (10.6.4)
  • Jolly Giant Level 7 Level 7 (25,440 points)
    27imac wrote:
    Does my Mac have a virus?


    whatever plagues your Mac, it certainly is no virus. there are no viruses that would affect a Mac. click _*Macintosh Viruses*_ and here for more information.

    When the Mac boots up, right after the Apple logo is gone and right before the blue screen shows there is a strange "twitch" or splotch on the screen of gray. The best way I can describe it is a very quick gray "snowy" image and then it goes to the blue screen. I never used to have that until a few days ago. My Mac is still under warranty. What should I do?


    run _*Apple Hardware Test*_ to see if that comes up with anything untoward.

    if it don't, try _*resetting your Mac's PRAM and NVRAM*_.

    JGG

  • rkaufmann87 Level 9 Level 9 (50,010 points)
    As Jolly Giant mentioned it's definetely not a virus. However you did say you are covered by the warranty so why aren't you taking advantage of it? If your machine is less than 3 months old you have free AppleCare telephone support, the number is in your owners manual.

    If your machine is over 3 months you can take it into to be looked at or your can purchase AppleCare which extends to warranty and telephone support to 3 years from the original date of purchase.

    Regards,

    Roger
  • Dave Barnes Level 4 Level 4 (2,975 points)
    If you have not done it, BUY AppleCare.

    Three (3) years of peace-of-mind. (We used to have a local electronics chain here in Denver (Fred Schmidt) that actually called their extended warranties "peace-of-mind". I thought it was brilliant marketing.)
  • 27imac Level 1 Level 1 (5 points)
    I reset the PRAM and the problem went away, but now my Mac starts up at its brightest screen setting, and then goes down to the my custom brightness setting when it goes to the desktop. How do I make it start up with my custom brightness setting like it used to?
  • Jolly Giant Level 7 Level 7 (25,440 points)
    i believe resetting the PRAM will have returned the Mac to default settings. i think if you re-apply your custom brightness, then reboot your Mac, it should show the old behavior. i'm not certain about this, however, because i did not yet reset the PRAM on my iMac.

    JGG

  • 27imac Level 1 Level 1 (5 points)
    I did put it at the custom bright setting, and it keeps happening. It doesn't bother me, I just want to make sure that's normal. Also, most of the settings are like how I had them before.
  • babowa Level 7 Level 7 (27,690 points)
    I use Shades to control my screen brightness and my iMac always at first displays the default startup settings; as soon as everything on the desktop is being loaded, my chosen screen settings kick in, so I'd call that just normal behavior.
  • 27imac Level 1 Level 1 (5 points)
    What happens if you install Mac OS X using the disc that came with the Mac without deleting the hard drive?
  • babowa Level 7 Level 7 (27,690 points)
    Why do you feel it necessary to reinstall?

    The operating system is written to start things in a certain order, so as long as you wind up with the exact settings you want at the end of the bootup process, I'd say all is as it should be.

    I don't know which OS version yours came with. If you do not choose erase and install - which was available with 10.5, but no longer an option with 10.6 - it should simply reinstall the OS portion and leave all your other files untouched. If there is some sort of problem with any of those, you haven't gained anything. Depending on the exact version yours shipped with, you'd have to apply all software updates again, which would be best done by downloading and installing the combo update. Then run Software update to install any other updates (Safari, iTunes, etc).

    If whatever is happening is bothering you, you should follow the other posters' advice and either call Apple or make an appointment with the Genius bar so they can have a look at it.