Mac Pro built in 2016 no longer will come up. Only way to access is by option key on start up. Was able to access eDrive, ran TechTools and message was the can't repair Mac HD and to reformat (Volume Structure failed). Need help to accomplish this. Am not able to access Recovery 10-12 or the bootable disk. System is backed up on external hard drive. Thank you!
If you can't access Recovery, can you boot off the backup drive? If it's external, attached via USB and formatted as GUID, you should see it when you use that Option restart. Then, you can use THAT Disk Utility to reformat your drive, and whatever cloning software to clone your stuff back to that internal drive. I suggest STRONGLY that you actually do the reformat after clean installing the OS (because that's the best/easiest way to automatically recreate a recovery drive), then migrate from your backup drive.
Also - although it's a bit of a financial risk - this app has rescued the Volume structure of MANY hard drives I've known over the years. It's not always successful, but it's saved a LOT of clients who's files weren't backed up, despite my never-ending warnings.
Thanks S_Gans, I ended up taking it to my IT guy and he ended up taking it to Apple as it is still under warranty. It's resolved for now but I continue to hold my breath as this is the third go round and I still do not trust.