won't let me preview files, immediately switches to outline mode.
When I have a file with multiple patterns in multiple places, save the file close out and when I reopen the file as soon as I move something or zoom in I get a prompt that "Can't finish previewing. Could not complete the requested operation"
Can you please share the file with the team for investigation? Email it to firstname.lastname@example.org and put the link to this report for tracking: http://illustrator.uservoice.com/forums/939477/suggestions/47244215
What is your OS? Your GPU? The GPU driver version? Other system details? The version of Ai you are using?
Does it help to remove some patterns? remove other objects?