I had this issue on my laptop that whenever I rebooted it, a white explorer box that was completely blank with no messages appeared. If I clicked OK it disappeared, it seemed to do no harm however it was annoying. My laptop is Windows 8 however Ive heard of this issue on Windows 8.1.
Its basically an issue where an app you no longer uses tries to run at start up, to resolve this issue we delve into reg edit. Browse to the key below.
Then delete the empty “Load” key by right clicking it and selecting delete. Then reboot the pc in question and the issue will be resolved