A valid DVD drive could not be found. Error -70012

[Reign of Error]

Hello
a virgin poster here. Can I ask for help for a solution I cannot find by "googling"?
Firstly I have a Macbook which I have removed the internal Super drive. I've replaced it with a SSD/tray.
I also purchased a case for the Super drive to be used as an external USB DVD.
I have modified the DVDPlayback.framework file to look for an external DVD rather than an internal one as per these instructions: www.cnet.com/news/addressing-dvd-player-error-70012-when-using-external-drives-in-os-x/
The problem I have now is permission to replace the original DVDPlayback.framework file with the modified one. Library folder is read only for everything except System, which you would expect.
Is there any other way to replace this file ie via terminal? Or can I change permissions of this particular folder "/System/Library/Frameworks/DVDPlayback.framework/Versions/A" to read/write?
I'm using El Capitan.
Many thanks.

 

[harryb2448]

It is simply not designed to work that way. If you wishes to say BootCamp the option is to place it back in and proceed. Check out these rsposes:-


http://www.mac-forums.com/os-x-oper...optical+drive+and+will+not+connect+externally

And:-


http://www.mac-forums.com/os-x-oper...optical+drive+and+will+not+connect+externally

 

[Reign of Error]

Thanks harry.
Those two links shed plenty of light on the issue.
I can live without native DVD Playback, 3rd party software works fine.
It will come in handy for accessing data from the occasional disk too.