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Mike Retondo Author

Level 1

28 points

10.9.3 = major problem with fast user switching

I've found a major problem with the 10.9.3 update with my 27" iMac, you probably won't see it if your on a laptop. I did all the updates in past few days i.e., 10.9.3 combo update, iTunes 11.2.1.

Afterward I noticed a bug when Fast User Switching i.e. FUS. I have 5 accounts but the bug can be replicated with only 2.

I login to userA have some windows open but you can just open a Finder window. Now make the window at least half the with of the screen and move it to the right side of the screen. Then login in to userB and setup the windows the same way as userA. Now FUS to userA and then back to userB. You will notice that the Finder window has been moved to the upper left corner of the screen. This problem happened's to all user accounts you login to except the first account you logged into.

Since I didn't know what update caused the problem I had to use Time Machine to revert to my last version of 10.9.2. I then double checked the for the bug and sure enough everything was working fine. I now was going to install one update at a time and to see which one was causing the bug. So I installed 10.9.3 first and found the bug immediately.

I now know what's happening. When the switch occurs the screen is resized to about the equivalent of a 13" MBP. At this point the windows that fall some ware outside that size get moved to the upper left corner and resized. Then the screen resizes to normal but it's too late, all the window have moved and been resized to fit the 13" screen size.

You can reproduce this effect by going to System Preferences and selecting Display and then select the Scaled radio button. No select the smallest size, say, 1280 x 720. Now select the Best for display radio button again. You will now see all the windows you have open that were too big no moved and resized to the upper left corner. I know why the Mac moves the windows, it's so you don't have any windows stuck off screen.

Now when I say 13" it could be some other size but it's about that size give or take.

iMac (27-inch, Late 2012), OS X Mountain Lion, 1TB Fusion Drive

Posted on May 25, 2014 12:10 PM

55 replies

Jul 2, 2014 10:53 AM in response to a brody

Oh... just found the email in my inbox. The moderator removed my post because :

" We’ve removed your post ... because it contained either product feedback or feature requests."

Well, that explains that then.

DY-E

Level 1

20 points

Jul 2, 2014 4:50 PM in response to a brody

Hi a brody.

Yes, if you're happy to post a user tip with my instructions, that would be great. Just reference back to this original discussion as usual...

Cheers,

Jul 24, 2014 2:22 PM in response to Mike Retondo

Just downloaded Yosemite public beta and fast user switching seems to be fixed.

Barney-15E

Level 10

116,746 points

Jul 24, 2014 4:19 PM in response to bobcrossley

Good job abiding by the non-disclosure agreement.

a brody

Level 10

84,049 points

Jul 25, 2014 5:14 AM in response to bobcrossley

Just be sure it is finally fixed in the final release. Stay on top of it. What's fixed presumably in one beta release may not be in another. And it is up to people reporting at http://bugreporter.apple.com/ to keep Apple aware of what is going on. If you are able to keep a partition of 10.9.4 and Yosemite on your machine, you may want to see if it gets fixed on future releases of 10.9 and let Apple know its status under 10.9.