This could be due to networking problems. Try the following (one change at a time, so what we know what actually caused the problem when it goes away):
- Open Reader's preferences and go to the "General" category. Uncheck the two "Show online storage..." options. This will not connect to Adobe's "Document Cloud" when you try to open a document.
- Open Reader's preferences and go to the "Documents" category. Set the number of files in the recently used list to 1 (this will remove all your files that you have recently used from that list). If this fixes your problem, then there may be something wrong with one of the files that you've recently used (e.g. a network drive no longer being available).
- Open Reader's preferences and go to the "Security (Enhanced)" category and set "Protected View" to "Off" and uncheck "Enable Enhanced Security".
Does any of these fix your problem?
Karl Heinz Kremer
PDF Acrobatics Without a Net
PDF Software Development, Training and More...
http://www.khkonsulting.com