First, as the DVD playback is a Plus feature, you need to be signed in to your Plus account. To activate the Plus features, you should sign into the RealPlayer software. If you are already signed in, please sign out and sign back in.
If it crashes when you try to seek ahead during the preview, please follow the instructions from the link below:
If the issue persists, please provide the following information:
• Is this happening to all DVD's or just with a particular one?
• What version of RealTimes or RealPlayer is installed? (See https://customer.real.com/hc/en-us/articles/204039513)
• Do you have any security software installed (Norton, McAfee, AVG, etc.)?
The more specific you are, the better I will be able to assist you.