Why does Windows 8.1. allege that 'this DVD-ROM drive is read-only', when it's not?

Question

I've 2 kinds of blank DVD-RWs: Sony ("S" henceforth), and Memorex ("M"). I performed everything on the same computer and DVD drive. When I tried to write files to a blank M using only Windows (no software), the burning stopped and this message arose:

This DVD-ROM drive is read only. You can copy files to this writable DVD, you must insert it into a writable drive.

But I successfully burned a S, before this attempt with M. So I removed this interrupted M, and tried to burn another S, that did burn successfully. Then I reattempted to burn M, and the error message overhead reappeared. Are all M discs corrupt? How can I check this, before discarding them all?

Answer 1

RW media are tricky. First, they say they take speeds "up to", but in my experience slow and easy does it. Set up the write speed as slow as possible. You may need some burning software for that, as MS built-in can be spotty. I am unsure whether MS's built-in allows selection of write speed.

Secondly: unfortunately producing reliable RW requires good manufacture. I never had problems with Sony RWs, but Verbatim/Memorex/previously-unknown-MFR had their issues. This may be media issue, so I would RTS'd them. I personally stick to TDK's as they ALWAYS come through. Admittedly, I've dropped RW in favour of USB's/email/cloud, so now basically just Rs. But they are in data media like Canon is in printing (pop it in and it works).

Thirdly: whenever possible, I'm using +R/RW instead of -R/RW. I've found it much more stable and reliable, with much fewer issues during and after writing, and then later use.

Last thing: how old is the burner itself? Current crop of drives are pretty reliable up to one year with normal use, after that beam power drops significantly, causing issues exactly like this.

Update: I just remembered that RW does not like exposure to strong light, especially sunlight. It has to do with technology. I had several going bad after checking them for scratches against window in summer/ strong sunlight.