Drive 1 (boot drive) has been working.
Today I added Drive 2 (data only). The computer won't boot now. What did I do wrong? Followed these instructions:
Located new HD in Disk Utilities, clicked erase tab, macintosh..., erase, erase and named the new drive "data drive". It seemed to format it and the computer worked (OSX 10.6.8 Snow Leopard worked). Then I shut down and restarted only to get a blank screen? Thanks.
Mac Pro, Mac OS X (10.7)
Sounds to me like you erased Macintosh HD that held OS X.
I positively selected the new HD and noted the OS X drive was still named properly (nothing had changed) re: the original name). I was then able to do some work on the computer (in OS X) before shutting down. How would you find out?
never start something without one and preferable two backups
but you cannot unmount and therefore cannot erase the boot drive you are using, not possible, like "pick yourself up by your own bootstraps" would be.
Something else, so use the OPTION key, use the OS X DVD, clone your drive or use the Source and Target Destination tab in DU. And setup TimeMachine.
Buy a drive or three, install OS X for emergency use only, setup anotehr as the alternate bootable backup of the working system.
Always be ready to restore your data or system if needed - don't wait until you have to. Do a dry run once.
How would I know if I erased it? How can I check?
Let's assume instead this is a huge coincidence, and has nothing to do with your recent drive activity.
I shut down and restarted only to get a blank screen?
There are many things that could cause a blank screen.
Hold down the Option key at Startup to run Startup Manager. Its simple code is all in ROM. It uses the simple display method. It should draw an icon for every Volume that appears to be bootable.
¿Does the display stay dark?
--Yes, your graphics subsystem is in trouble.
--No, Simple graphics is working.
¿Is there an Icon for your Macintosh_HD, Recovery_HD, and any other Volume with any kind of System on it?
--Yes, all are present. Debug Macintosh_HD using Safe Mode.
--No, Macintosh_HD is not present. This would indicate it is badly damaged.
--No, no bootable Volumes are shown. This indicates EFI_Boot and Recovery_HD and Macintosh_HD may all be damaged.
Very helpful. I rebooted by holding down Option key and everything is there (both hard drives, partitions, appropriate names, etc.). Clicking on the boot drive (from Option key boot up) takes me to the home screen actually where I can work normally. You recommend debugging with safe mode for this? I apologize, I am a brand new Mac user, so how do I do this? Thank you!
If you can get to the login screen, you are fine already.
use System Preferences > Startup Disk ...
... to set the correct disk
--------
To invoke safe mode (which does not appear to be necessary at this point) Hold down the Shift key as you restart.
This will run one pass of Disk Utility ( Repair disk) on the way up (so it takes five minutes) and then start up with minimal extensions loaded. You must login, at a screen that says Safe Mode in Red, even if you normally auto-login. This mode is helpful for moving, deleting, installing and re-arranging -- especially Extensions, since most are not loaded. There is no graphics acceleration, as the graphics Driver is not loaded.
Fixed.
"System Preferences > Startup Disk ...
... set the correct disk" fixed the problem.
Thank you!
You have 10.7 so I would use Recovery mode partition, has DU and Startup Disk
adding a 2nd Hard drive (for data only)
