www.makemkv.com

I've got a few discs that I've backed up without decrypting.

Is there a way I can use the encrypted folder backup as a source and have MakeMKV make an decrypted backup, or do I need to backup and decrypt my original disc?

I know I can rip titles from the encrypted backup with MakeMKV, but the backup option is greyed out.

Yes, you can "mount" the encrypted backup folder as a virtual drive (there are many free programs available that will do this and I believe the later versions of Windows have the facility built-in), then choose that virtual drive from the "Source" drop-down box in MakeMKV as you would a regular optical drive (IE. if your optical drive is D: and you assigned the virtual drive to E: then choose drive E:) but do not "Open" the disc.

Doing it this way means the "Backup" option is still available within MakeMKV so you can now do the Backup again but this time choose "Decrypt video files".

EDIT: I forgot to mention... Choose a different location to the original encrypted backup, or change the name of the decrypted backup destination folder, otherwise you may be trying to overwrite files as they are being read!

SECOND EDIT: I also forgot to mention that you will need to "un-mount" the virtual drive again once your done, otherwise Windows won't allow you to delete/move/rename it.

Thanks for the suggestions.

I tried using imgburn to make an iso of the folder, mounting that iso as a virtual drive, with imdisk an old program that mounts ISO etc as virtual drives but - more usefully before solid state storage became popular - allows you to create drives in RAM, but MakeMKV doesn't see it upon start up. Opening the iso as a file removes the option to 'backup', only save titles.

I then tried mounting a folder as a virtual drive using the windows cmd prompt 'subst W: <path to folder>' but this seems to mount the folder as a harddrive, rather than a removeable optical drive, and again, MakeMKV doesn't see it.

I agree with the theory, but I can't seem to make it happen in practice. Is this a method you've used or just 'it should work' ?

I have actually done this myself many times. I'm still using Windows 7 so I downloaded a program called MagicDisc, but that was some time ago and the links to their home page no longer work (I'm guessing that Microsoft adding the functionality to Windows drove them out of business).

According to Google, all Windows versions after Win7 supposedly have it built-in. From the first result of a Google search:

How do I Mount an ISO as a virtual drive?

Mount the ISO File in Windows 11, 10, or 8.1

Download the ISO image, then open File Explorer and right-click on the file. From the pop-up menu, select the Mount command. This will open a virtual drive that is visible in File Explorer

And I just did this again myself to check that it still works. I mounted the .iso image as a virtual drive, Windows Auto-Run then popped up asking me what I wanted to do with the "disc" (I have MakeMKV added to my Auto-Run menu so) I opened MakeMKV and it automatically displayed the virtual drive I just created.

My Windows 10 doesn't have a 'Mount' context menu when I right click an ISO image.

But, PowerShell will let me mount an ISO in a way that MakeMKV sees with the command Mount-DiskImage <path to ISO>. And, I can unmount the ISO with the PowerShell command Dismount-DiskImage <path to ISO>.

MakeMKV works on these images as fast as my SSDs will read and write, so it's many many times faster than reripping my discs.

Thanks for all the suggestions, Radiocomms237!