White screen after waking up from sleep. Goes away when you move curser over it.

Hi, yes, a bug...

Resolution

Move the mouse or trackpad cursor over the center area of the login window so you can see the user icons. Click on the icon of the user that you would like to login as, type in the user's password, and press Return.

If the login window is configured to show only the name and password fields, type in the user's name and password into the fields, and press Return (even if you cannot see the rest of the login window).

Additional Information

This issue will not occur if the display is not sleeping when the account is logged out. Use the steps below to confirm that the account is not configured to log out automatically while the display is sleeping:

1. Open System Preferences > Security & Privacy > General. Click the padlock to unlock the preference pane and enter your admin password. Click the Advanced button at the bottom, then see if the option "Log out after N minutes of inactivity" (where N is the number of minutes) is enabled.
2. Open System Preferences > Energy Saver and configure Display Sleep to occur after the account is logged out, by dragging the slider to a number of minutes that is greater than N was set to in the previous step.

Important: If automatic log out is not needed, disable "Log out after Nminutes of inactivity" in System Preferences > Security & Privacy > General. This will also prevent the issue.

http://support.apple.com/kb/TS4135?viewlocale=en_US

Great, it's a bug. I have the same problem but I do not log out. I have to just keep clicking around the screen to get all the parts to show up. Only once so far have I had to to do a hard shutdown to get the screen back normally. I appreciate knowing my lattop is not on it's last legs.

This same thing has been happening to me, Diane1349. I didn't have the problem until I upgraded my iMac 12,1 to Mt Lion. It is kind of annoying and only happens when the computer goes to sleep on its own. I went into Desktop and Screen Saver and set a 'hot corner'. I just have to remember to move my mouse to that corner to sleep the computer or do it from the Apple drop down menu when I am walking away from my computer. Hope a fix comes out for this bug.

Hadn't thought of doing that. I'll try it. What's really odd...I use my laptop and a monitor so I have two screens. If the one on the laptop is white I take the other screen and 'wipe' it over the white one and it magically appears. Does indeed seem to be an update related problem. Thanks

so you are still logged in ? if you had a lot of things open it could take awhile for it to get ever thing open and show the desktop. are you waiting or will it stay white until you do some thing ?

It's white when the laptop wakes up and nothing is open except maybe mail and a web browser. It's just a random occurrence. Laptop is asleep and then when I wake it....white out. Since I'm trying to use it I don't wait very long. Maybe next time I'll just walk away for awhile and see what happens. So my laptop screen goes white occassionally and my iPhone screen goes black....another problem, another time. At least it's under warranty.

I am having the same problem as everyone else. Sounds like a bug in Mountain Lion.

I am having the exact same problem and I did not have this problem before Mountain Lion

I've recently installed Mountain Lion 10.8.5 on my Mac Pro (mid 2010) and I'm experiencing the exact same white screen after waking the monitor from sleep n.b. the computer is set to never sleep and I never log out, so the earlier solutions proposed don't work or apply here.

I never had this before with Snow Leopard, so suggestions would be appreciated; incidentally, I've already tried reinstalling the new OS and that hasn't cured it either.