Hello World....can anyone out there solve this ?

Question

am hoping someone will be able to help please, after three days of battling an upgrade that went wrong. I've documented this as fully as I can since I see a lot of comments from people trying to help here asking for specific steps that we (those of us with the problems !) have undertaken. Sorry if its a bit long :
I have a 27" iMac 2010, and I think it was running OS X Lion or Mountain Lion (can't see anymore !). In retrospect I'm not sure if this was the correct upgrade step, but I tried to upgrade directly to Yosemite over the weekend, and after completion the Mac rebooted straight into Recovery mode. The internal  Macintosh HD SATA Drive was locked, even though I did not have File Vault switched on. I was able to unlock it by first selecting it as a reboot drive, unlocking it and then going back to the Recovery screen to select Time Machine Backup. However, my Time machine backup, on a WD My Book Live Duo, failed to work - the OS could not see a valid TM backup. It was at this multiple failure point I began to show some signs of slight worry...........
So, I tried to download OS X Lion from the internet (Recovery mode option). The download worked for the US Store only (not UK where not available), but still failed to boot in anything but recovery mode.
I tried Command -R, Option boot etc etc but still the same recovery screen appeared.
I then went into Disk Utils and saw that my Macintosh HD with all my data was greyed out and showed a locked logical partition. I tried to get around this by re-selecting it as boot drive, unlocking it and then returned to the Disk Utils window. This then showed it as a verified SMART drive. I verified the disk and repaired any broken links etc. Still it would not reboot into anything but Recovery Mode, reverting again to a locked logical partition for the Macintosh HD internal SATA drive after each reboot.
So I then unlocked it as before, and tried to Option- turn off Encryption in the File Menu. An error message stated that it was unable to turn off encryption.
I'm thinking I'm stuck....then I went back into the Terminal Window and accessed the /dev that is the Macintosh HD SATA drive. Under /Users/username all my data was there intact !.
My last step was to go back to Disk Utils, hook up an empty 2TB external WD elements drive and then select it as Restore Drive for the Macintosh HD. It took 20 hours but all the data (not Apps) was copied to it. So at least I got the data.
I could now completely erase my HDD and start again afresh, but if I could find a way of getting back in so I can see if I could at least solve the problem, since it doesn't seem to me to be a hard drive failure issue, but more of an OSX installation error. Is there any solution that you  are aware of that could get me back to a position where my Macintosh HD could reboot and allow me access to my files and maybe even try to figure if I can restore what I thought was Time Machine via the OS-X. I don't want to just trash the drive before understanding if it can be at least restarted.
Thanks very much
Paul

Answer 1

but as I said though, File Vault was switched OFF.
Okay, but it was hard to tell since your initial post is contradictory.
even though I did not have File Vault switched on.
Followed later by:
and tried to Option- turn off Encryption in the File Menu. An error message stated that it was unable to turn off encryption.
So was FileVault on, or off? There can't be any encryption to turn off if FileVault was never on.
I verified the disk and repaired any broken links etc.
Did you do a literal Verify Disk rather then the button below that, Repair Disk? If you did not do a Repair Disk, then nothing was fixed. A verify only looks for problems and reports those it finds, but does nothing else.
Regardless, the main partition is in an unstable condition. At least you already have the data backed up. When you boot to another drive so you have a normal desktop, can you access the files on the external drive you did a Restore Drive to (the one that took 20 hours)? Or is that as inaccessible as the main drive?
since it doesn't seem to me to be a hard drive failure issue, but more of an OSX installation error.
That's also the way I see it at this point. Though not necessarily as OS X issue. A power outage or brown out can seriously trash a drive that was in write mode at the time. A really good way to trash the file table and boot cylinder.
The only way (at the moment) I can think to try and salvage the drive is to run Repair Disk. If it returns that it fixed any errors, keep repeating the command until it reports no issues. That's the free method. DiskWarrior is a far superior tool for fixing file table damage. But either way, you're eventually going to end up with a fixed table that may lose connections to the files they point to on the drive as entries that are too damaged to be repaired will be removed. However, you do have the copy, and the copy will have a clean file table to retrieve lost files from. The point is to repair the drive's ability to write data to it again.
I tried Command -R, Option boot etc etc but still the same recovery screen appeared.
Command+R and Command+Option+R are similar, but use a completely different approach. Both show the exact same work screen, but the first boots to the hidden recovery partition, so you are still booting to the hard drive. The second boots to firmware, so you are not working off the hard drive at all.
If the drive can be repaired enough with Disk Utility or DiskWarrior, then try reinstalling OS X again. Though personally, with a drive that badly trashed and the data backed up, I'd boot into Internet Recovery Mode (Command+Option+R), and use Disk Utility to completely repartition and erase the drive, then reinstall everything from scratch. But that's me.