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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

Mike Retondo Author

Level 1

28 points

May 26, 2014 12:15 PM in response to Barney-15E

That's exactly what is happening. If you manually switch screen resolutions to the smallest and then back to "Best for display" you'll see the effect.

Mike Retondo Author

Level 1

28 points

May 26, 2014 12:17 PM in response to bobcrossley

Weird that your window went to the upper right unless you have two monitors with the one yours showing is to the left of the main screen because the upper left of the main screen has the origin 0,0.

Mike Retondo Author

Level 1

28 points

May 26, 2014 12:28 PM in response to Mike Retondo

Ment to say.

Yes, it's when you user Fast User Switching.

Here's a snapshot when first loged in but before the screen resizes back to normal. Notice that the Dock is even shown at the bottom of the Yellow area. Ignore the window in the lower right, I moved it from the upper left before taking the screen shot.

May 27, 2014 2:14 AM in response to Mike Retondo

Same problem here. Happened sometimes previous to 10.9.3. Since 10.9.3 it happens every time I switch between users. The screen stays OK for the first user that logs in but is temporarily smaller for everybody that logs in after that.

Consequently all open windows are moved to the topleft of the screen. Sometimes impossible to grab them back.

Very annoying.

Drew Saur

Level 2

189 points

May 27, 2014 3:35 AM in response to Mike Retondo

I see this, and from experimentation, I think this may be a permissions-related issue. It seems to happen to any user who is NOT the first logged-in user after the machine starts. Can anyone else confirm this?

Drew

May 27, 2014 6:30 AM in response to Drew Saur

In my situation that seems to be the case. The first logged-in user is not affected.

Mike Retondo Author

Level 1

28 points

May 27, 2014 6:42 AM in response to Drew Saur

Confirmed, I said the same thing in my origial post.

Drew Saur

Level 2

189 points

May 27, 2014 7:04 AM in response to Mike Retondo

Apologies. I missed that little tidbit in your third paragraph.

Drew

May 27, 2014 12:10 PM in response to Mike Retondo

After multiple experiments on multiple machines today I found that all 10.9.3 machines experienced the same issue. I could not find anything common between them, this does not seem to be an issue with a specific softwarepackage.

Mike Retondo Author

Level 1

28 points

May 27, 2014 12:44 PM in response to Ernst Mulder

You're right, I reformatted my drive and installed a fresh copy of 10.9.3 just to be sure there were not third party conflicts and could still replicate the bug.

Mike Retondo Author

Level 1

28 points

May 27, 2014 2:26 PM in response to Mike Retondo

Apple has confirmed this bug to me and are working on a fix.

Jun 3, 2014 8:08 AM in response to Mike Retondo

I have observed a very similar issue, quite repeatable, on a Macbook Pro Retina without any external display.

When I fast user switch (FUS) between two user accounts, the one that I logged onto second has all kinds of window positioning issues. Apps that I left in one position will have moved elsewhere on the screen, often hanging partway out of the visible space.

It's definitely not a third-party app problem. I don't have any apps installed that manage screen layout, and I've observed the symptom with Apple-provided apps including Finder itself.

The symptom is intermittent and doesn't happen for me on *every* FUS, but it happens quite often, and a reboot didn't fix it.

Jun 13, 2014 4:07 AM in response to Mike Retondo

Thank god I'm not the only one who finds this unbelievably annoying.

I am using a 21" iMac and this started to happen after the 10.9.3 update.

I have two user accounts because we both have different native languages (English and Spanish)

Like everyone, the "auto-login" account is unaffected (my "English" account), but any subsequent accounts... (including the GUEST account ! ... check for yourselves!) ... also show this strange "resize" issue. It affects not only the desktop background but the dock too.

I hope 10.9.4 fixes it.

blcarson

Level 1

0 points

Jun 15, 2014 3:53 AM in response to Mike Retondo

Although it's not a great solution, hiding your windows before you switch will allow them to return the proper spot once you switch back and show them again. Still annoying, but slightly less so then having to reposition them every time.

blcarson

Level 1

0 points

Jun 15, 2014 4:38 AM in response to blcarson

As another temporary solution, the app Stay seems to do the trick in so far as snapping everything back into place once you switch users;

https://itunes.apple.com/app/stay/id435410196

10.9.3 = major problem with fast user switching