DVD's won't play in certain players/comps.

Not all players will consistently play burned media.

They've tried them on 3 different computers and they all have the same issue. Could it possibly be the dvd is not compatible with certain drives?

I forgot to put that it's on DVD-R media and was burned through Adobe Encore.

I've had this too. But as mi1ez says it's drive dependant. I've got a few Pc's and it just boils down to some burners just work better.
I'd like to say it's make dependant but most my drives are LG and i still get the problem if i burn with a certain burner.
You could try burning the discs slower, i thought about seeing if that works but never got round to it.
Found the drive that works 100% and burn everything using that drive

Ok i'll look into that. Thanks for your help.

You're possibly burning too fast for the media and as a result the data can be a bit patchy - less sensitive drives will choke.

Best thing to do is burn your discs at the lowest possible speed and test them on the troubleshome drives/players and see if that helps.

If yes, every time you burn take the speed up a level until you max out. If no, try changing the media to a different brand.

Also be aware of + and - R - all drives can read -R but only +R drives can read +R.

Don't forget that +R's need to be finalized, altho most writing programs do that as a matter of fact (except my 3 liteon standalone recorders) anyways. I use +R/RW's almost exclusively in all my recorders. 3 Standalone Liteon, a Plextor 755SA, an LG CCW-h20L (which relaced a good Samsung writer). Have not had a single problem with computer generated DVDs playing in several DVD players (Sony Blu-ray, Lite-on, Cheap Desay, and old sony, and several others.

(1) I always burn a DVD at no more than 8 X (I've burned several at 12X and 16X and they have played fine).
(2) I never by media made in china or India. Use to buy by made in Japan but can not find so I now buy made in taiwan. Never Buy off the wall brand, and only stock up when on sale.
(3) I always do a quality scan of a DVD movie to check the media/lot (batch). I use plextools and nero for the scan check. (there was a registry change to allow Nero to use samsung drive. Have not tried to do a quality check using the LG H2OL drive.