I second what bjkg said. :iagree:
My Matshita UJ-840S (not 850S) is extremely picky about DVD media, and the best I have found for this drive is Taiyo Yuden 16x DVD+R media (media code YUDEN000 T03).
My drive also burns with poor quality when using the maximum burn speed (8x) so dropping burn speed down to 6x or 4x can help in many cases.
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