Just curious;

Did you clone to an external drive before you upgraded?
Some of the information I've read recommends having 2
back up drives. Time machine and an external cloned drive.

Additionally after I clone a drive & verify the cloned drive
will boot then I unplug all external usb and firewire gear
then I do the OS upgrade. If all goes well I will plug in
the time machine drive, erase it, then let it backup overnight.

What process did you use?

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