No, this error "$MFTMirr does not match $MFT (record 28)" has nothing to do with boot mode - it's a file system issue that can be fixed sometimes by performing "chkdisk.exe /f" on that filesystem.
But sometimes even "chkdisk" won't help, most probably because of that: """ apparently Microsoft has changed the rules for copying $MFT into $MFTMirr """ For more info see this bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1527231 I actually had that problem with a 3 TB NTFS volume, but now I cannot reproduce it because of not using that disk any more. ** Bug watch added: Red Hat Bugzilla #1527231 https://bugzilla.redhat.com/show_bug.cgi?id=1527231 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1774855 Title: Unable to install Ubuntu 18.04 as a secondary OS with w10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1774855/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs