condition memory and last memory are gone when take out DVDs

I have several successes in creating DVDs that can playback in my pioneer dvd player. Sometimes I did not finish the DVD and wanted to resume from where I stopped. I used last memory. Whenever I took out the DVD, last memory is gone. What should I do so that my dvd player will "remember" that dvd. I did give each dvd different volumn name when I created them. Thanks!

 

the best thing i can tell you is to not try an burn at different, just do it all at once. Are you using Re-writables?

 

I used both DVD+R and DVD-R. I usually create dvd image files and use Nero 6 to burn dvds.