I have a MacBook Pro with an internal SSD running OS 10.13. I have an external drive with OS 10.12 on it.
When I boot from the internal drive everything behaves normally.
When I boot from the external drive, the internal drive doesn't mount. Disk Utility shows that it is there but the Mount button is grayed out. I can't figure out what's going on.
I have a feeling the reason/solution is something obvious that I'm missing. Any ideas?
Thanks.
MacBook Pro
I'm not sure if Paragon make a macOS version of the APFS driver or not (it would be a paid app). Using a third party driver makes it more likely for you to have system issues. It is hard to say whether the driver would would be safe to use when writing files to an APFS volume. It would be better to store any items needed by both operating systems on a shared HFS+ formatted volume or a network share.
Aaaaahhhhhh I wondered if it might be something like that. Probably no workaround, is there?
Thanks
High Sierra converted your internal boot drive to the APFS file system. Sierra is unable to read or mount the APFS file system since it did not exist when Sierra was released.
Internal drive not mounting
