Jason,
Are you able to please share the original version of launchbox that first came with bigbox mode, I don't recall always having this issue.
From what I can see the only file being created when loading bigbox is the settings(timestamp).xml
There are 73 items that have their date modified time stamp adjusted when I boot big box, the largest of which is Documentation.pdf (742kb).
Not sure if this helps at all, but if I click anywhere else on the screen while it loads, the big box splash screen shows a black background.
Is there a means for me to monitor what BigBox might be trying to load in?