If you have a Slingbox PRO and are experiencing A/V sync issues, the first thing I would like you to try would be to check for any firmware updates for that unit. To do this, navigate to Setup.slingbox.com on a PC or Mac, click on "Get Started", select your Slingbox, then click on "Check for Updates". Also, does the A/V sync error occur when you connect on any other devices?
Awaiting your reply!
Sling Media Forum Moderation Team