Desktop icons are unexpectedly rearranged on a Windows Vista-based or Windows Server 2008-based computer even though the Auto Arrange setting is turned off
You configure a Windows Vista-based or Windows Server 2008-based computer to log on automatically on startup. However, after the logon process is complete, the icons on the desktop are unexpectedly rearranged. This situation occurs even though the Auto Arrange setting is turned off.
This problem occurs on certain models of computers. It is likely to occur on computers that have an extra-wide screen, such as a screen that supports a 1600 × 900 resolution. This problem may also occur on computers that have hybrid GPUs connected to one monitor.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB961085.