Hi guys, I am in need of some big help, here is what happened: (This is a 27" 2011 Imac). Regular 1TB hard drive, non-SSD. Accidentally updated HS OS two days ago, after a few mins i restarted and the system hung on the loading progress bar.... Decided to reinstall... used a HS boot usb and eventually it allowed me to reinstall. I then restarted and used the boot to restore from a time machine (few days prior to the update) It worked for a day...went to restart it and now its doing the same thing...although this time now it cant find the internal HD at all...well, it finds it maybe 1 out of every 8 attempts. I either have to sit and wiait for 5 mins before Disk Utilities will even show it When I click on it I can reformat it, but then the "install HS" option wont show the newly formatted disk (journaled) Also, when i click on this like Disk Utility or Install MacOS...it is sooo slow moving to that next screen.. Also, my Timemachine backup is on a 4TB extrenal WD drive...I partitioned the drive into an addle 1.5TB and installed HS on it, however, I can never boot from it? When I try to restart with option to select boot, it just takes me to disk utilities and never to HS... Im at a loss at this point... I tried again was able to boot HS but it is SO slow!! I downloaded Firefox and just the copy portion of the install to my applications took over a minute. Thoughts? Just trying this now the backspace takes a while to kick in It worries me that I can't boot from the brand new WD Time-machine backup partition. Can I even install MacOS on it? Why can't I select it when I install? The install process completes, but it doesnt restart to the select language screen etc... it just boots to the internal Mac OS... and if I erase that one, then it boots to disk utilities.