I have the CDV300x with a Sandisk Ultra 32GB card and my cam has been working fine for about a month without any problems. I don't live very far from work and its only about a 6 minute drive so it actually took about a month to fill up that card with video. I saw something happen the other day and wanted to review it on my dash cam and noticed that my cam stopped recording about 6 days ago and apparently isn't overwriting the oldest files. I have the overwrite option enabled in the options. Any suggestions? Thanks.