Big mistake....Problems with reverting back to Yosemite from El Capitan

[ToddJ]

I am an idiot....i upgraded to El Capitan from Yosemite on my main hard drive....I backed up everything via Time Machine which i thought was a good thing. I then decided to revert back to Yosemite since I didn't like El Capitan. I backed it up via Time Machine again and tried to revert back to Yosemite from one of my Yosemite Time Machine backups....Now when I try to boot, it starts booting like normal, but then starts over again....after doing a lot of searching on the internet it seems that I have to erase my hard drive in order to start over and then try to restore via a Yosemite Time Machine backup. (I read about someone who tried to restore a Yosemite time machine backup and only half of his data reloaded because El Capitan had changed the file structure of ALL his time machine backups....what is the best way to go about this? i have made a Yosemite USB drive from my other mac. I didn't want to erase the main hard drive, but it looks like there is no other option....any suggestions would be great! thanks

Update: I forgot to mention that when i do try to use Disk Utility to try to erase my hard drive on my iMac, it only gives me the option for 'First Aid' and Partition. It doesn't let met erase it (and I am using the Yosemite USB boot up to do this.)

 

[adrianlondon]

You could do a complete recovery and take your laptop back to the state you bought it in (should be an option under internet recovery I believe - I've never actually done this), then upgrade to El Capitan, restore your files, and then just copy them to another USB drive ready for putting them back after doing yet another restore, but obviously not upgrading beyond Yosemite. Or just stay on El Capitan. It ain't so bad

 

[Weaselboy]

Attach the TM backup then option key boot to it. That will get you to a recovery screen. Now in the Utilities menu launch Terminal. Then enter the command below to kill the core storage volume I suspect you have on there.

diskutil cs delete "Macintosh HD"

Be sure to include the quotes. I assume here your drive is named Macintosh HD.

Then quit Terminal and launch Disk Util. Go to the erase tab then select the drive brand name at the top of the left column (like Seagate 1TB or whatever). Now select Mac OS Extended (Journaled) and apply that format. Then quit Disk Util.


Now click restore and you will get a window that asks what date you want to restore from. Scroll down that list back to date that was still on Yosemite and select that, then click restore.

 

[Zakzilla]

Attach the TM backup then option key boot to it. That will get you to a recovery screen. Now in the Utilities menu launch Terminal. Then enter the command below to kill the core storage volume I suspect you have on there.

diskutil cs delete "Macintosh HD"

Be sure to include the quotes. I assume here your drive is named Macintosh HD.

Then quit Terminal and launch Disk Util. Go to the erase tab then select the drive brand name at the top of the left column (like Seagate 1TB or whatever). Now select Mac OS Extended (Journaled) and apply that format. Then quit Disk Util.


Now click restore and you will get a window that asks what date you want to restore from. Scroll down that list back to date that was still on Yosemite and select that, then click restore.

You actually want to hold 'Command' + 'R' instead of 'Option' to get to the recovery utility. Holding 'Option' is for the boot loader selection.

EDIT: Nevermind, apparently you can boot into TM backups. Good to know

 

[Weaselboy]

You actually want to hold 'Command' + 'R' instead of 'Option' to get to the recovery utility. Holding 'Option' is for the boot loader selection.

EDIT: Nevermind, apparently you can boot into TM backups. Good to know

Yes, that's what I was after. If you boot to the local recovery partition it won't let you manipulate the disk like I mentioned since you are booted to it. This gets you booted to a recovery section of the TM disk.