Additional information from other forum: http://forums.adobe.com/message/6308494#6308494
"We were using Acrobat 9 and 11. Both have been installed with the latest updates. Yes, the signatures are self-signed. If there are alot of signatures that need to be verified it can take 10-15mins just to open the PDFs either on a network drive or local desktop."
You can turn off "Verify signatures when the document is opened" preference in Signature Preferences.
Hi. Thanks for the response. Did uncheck that option and the PDF does open faster but we would like to verify the signatures. Anyone has ideas on how to do this? I'm assuming this is causing the slowness, however, I did import some of the certificates into the "trusted certificates" but the PDF still opens slow. Thanks.