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imac only has 2 resolutions

My wife's Mac changed resolutions - possibly as a result of running a full-screen game. She says it has happened before. I told her to reboot and let me know if that helped.


It didn't, so I went to settings to change its resolution, seeing only 2 options, 1920 x 1200 or 960 x 600.


I told her tonight to turn her computer all the way off, meanwhile I would see what I could find out.


What should I look at to trace down her problem?

24, Mac OS X (10.7), Home workgroup

Posted on May 10, 2012 7:05 PM

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Posted on May 10, 2012 7:10 PM

Try clicking Detect Displays in the Displays preferences. If that has no effect then try a smc and pram reset.

112 replies

May 10, 2012 7:40 PM in response to Howard Brazee

I already tried Detect displays before my post. I see now that she doesn't have a "gather windows" button.


I tried the smc by shutting down and unplugging for 15 seconds. That didn't do anything.


Then I shut down then pushed the on button and held command-option-p-r down. I got the white screen 4 times before I guessed I needed to let go of the keyboard. No change.


Did I do something wrong, or is there another problem?

May 10, 2012 7:48 PM in response to Howard Brazee

If it didn't work I don't know why you flagged my suggestion as correct.


I wouldn't expect you have a Gather Windows button if there is only one monitor, i.e., your iMac. Also there shouldn't be an Arrangement tab either.


The cmd-opt-p-r sequence, liek all the boot key sequences should be pressed immediately after the boot chime. The machine will reboot again shortly after that. You can stop pressing the keys when it shuts down to start that second reboot (this is explained in the pram reset link I gave you). If this sequence of two boots did not occur you didn't do the pram reset correctly.

May 10, 2012 9:18 PM in response to Howard Brazee

So smc and pram reset has no effect.


Safe boot has no effect.


I'm inclined to think it has nothing to do with that game and this failure is just a coincidence.


The only thing left I can suggest it run Apple Hardware Test. If the screen doesn't have or allow you to set the resolution when booted into AHT then it's time to take to apple for repair. I think your video card may have failed.


Intel-based Macs: Using Apple Hardware Test


OS X Lion: Use Apple Hardware Test

May 11, 2012 1:11 PM in response to Howard Brazee

The genius did two things I should have thought about:

1. Boot to an external drive - this showed all of the expected resolutions, indicating a software, not hardware error.

2. Ran a permissions repair.


While the permissions repair was being run, she checked databases and discovered that this problem gets fixed by reinstalling Lion.


So I went home and prepared to reinstall Lion. In a couple of days her computer room will be painted and re-carpeted. So I set it up in the basement, tested the access to the Internet, and rebooted with my OSX memory card pluged in (pressing option). I started to run Recover, but my computer says it needs to be connected to the Internet. I could not find anything to set up from this boot, so I will take the computer upstairs and plug the Ethernet cable in it and try again.


Meanwhile, how do I fix it so that next time I don't need the Ethernet cable?

May 11, 2012 1:29 PM in response to Howard Brazee

The genius did two things I should have thought about:

1. Boot to an external drive - this showed all of the expected resolutions, indicating a software, not hardware error.

2. Ran a permissions repair.


So after that did your system show the proper resolutions when you boot from it? I ask because if it did it would be one of the few instances I've heard of where repair permissions actually fixed something! Or...


While the permissions repair was being run, she checked databases and discovered that this problem gets fixed by reinstalling Lion.


...is this the "solution" the "genius" came up with because you still didn't get all the resolutions after the repair permissions?


So I went home and prepared to reinstall Lion. In a couple of days her computer room will be painted and re-carpeted. So I set it up in the basement, tested the access to the Internet, and rebooted with my OSX memory card pluged in (pressing option). I started to run Recover, but my computer says it needs to be connected to the Internet. I could not find anything to set up from this boot, so I will take the computer upstairs and plug the Ethernet cable in it and try again.


Meanwhile, how do I fix it so that next time I don't need the Ethernet cable?


Without an installer disk (or flash drive) I think you must have an internet connection to reinstall Lion.

May 11, 2012 7:59 PM in response to JazzmanJohn

Now that's scary.


I reinstalled Lion and it didn't help (the fix permissions had its normal non-effect).


So I took it to the Apple store again, and they couldn't solve it. Then ended up saying that I need to clear my disk, reinstall, then restore from back-ups. He was going to empty the disk at the Apple store, but since I did drop my backup drive earlier today, I told him I would do it.


I went home, and told Time Machine to do a backup (it was delayed). While that was happening, I went to my computer and noticed I'm not alone. Now I think I should wait to try my solution until we get further feedback.


My wife's computer is the last year with the old keyboard - and the last year with the box with the tab to make it easy to carry. My computer is a year newer. 2007 seems about right.

imac only has 2 resolutions

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