# ROUND TWO! "My Mac will allow only one app window to be open at a time.



## jbm4 (Jun 5, 2007)

First:
___________________________________________
MY SYSTEM:
Model Name:	iMac
Model Identifier:	iMac8,1
Processor Name:	Intel Core 2 Duo
Processor Speed:	3.06 GHz
Number Of Processors:	1
Total Number Of Cores:	2
L2 Cache:	6 MB
Memory:	4 GB
Bus Speed:	1.07 GHz
Boot ROM Version:	IM81.00C1.B00
SMC Version (system):	1.30f1
Model: Hitachi HDS721075KLA360
OSX ver 10.6.8

MY ISSUE: **THIS IS ROUND #2 WITH THIS ISSUE!** It was resolved once before here. See: :http://forums.techguy.org/apple-macos/1026752-my-mac-suddenly-will-allow.html ....

....Now it's back again. That last solution seems not to have lasted! My Mac will allow only one app window open at a time. That is to say, if I have Mail open, then I open Safari, Mail hides in the Dock. Very annoying, I can't even get a screen capture because no window will remain open when I open my Screen Capture app!

Have tried everything:

No, I do not use Spaces or Expose; or Parental Control. 
I have not inadvertently turned on Single Application Mode. 
The pull-down menus in apps "Show All" makes no difference; 
my "Option" key on keyboard is not stuck (just to make sure this was not a keyboard issue, I installed a new wireless Apple keyboard - no change!)
Have re-set PRAM. No change!
Have set keyboard modifier keys to Default. No change!
Have used Time Machine to restore system back to a time before this issue was happening. No change!
Have re-installed Snow Leopard. No change.


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## Headrush (Feb 9, 2005)

Have you repaired permissions using Disk Utility?
Could be a corrupted preference file.

Does it behave the same in every user account?


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## jbm4 (Jun 5, 2007)

Hi Headrush:

Yes, behaves same in "Test" user account. Yes, have repaired permissions.No change!


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## allnodcoms (Jun 30, 2007)

OK, have you tried turning on the Guest account and playing in there. The Guest account doesn't save between sessions, so if it's happening there it looks like an OS issue (even though you have re-installed it... Strange! Was it a clean install?).

I can't see it being a hardware issue, that doesn't make any sense, so it's got to be OS or a spurious setting. If it is a setting it's probably going to be in your Finder Prefs (/Users/user_name/LibraryPreferences/com.apple.finder.plist). This would not survive a complete OS restore, but it would survive a repair / partial install. Can't think of anything else at the moment, but if I do I'll post it here...

Good Luck

Danny


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