My mac got formatted...!!!how to get my mac os back or reinstall it ....???
My mac got formatted accidently while installing windows...!!! How to install mac os back...???
MacBook Pro, OS X Yosemite (10.10.3)
Power on your Macbook Pro and immediately press and hold CMD+R to boot to recovery:
OS X: About OS X Recovery - Apple Support
If you cannot access OS X Recovery, then boot to Internet Recovery by holding ALT+CMD+R.
Once OS X Recovery is loaded, connect your Macbook Pro to Wifi if necessary and choose Re-install OS X from Utilities Window:
If You do not have an access to Macintosh HD, then you might have to first re-format disk/partition:
OS X Yosemite: Erase and reinstall OS X
If your Mac is older generation Mac, that came with OS X 10.6.x Installation Discs, and you do not have access to Recovery Partition, then you might have to install 10.6.x Snow Leopard first, upgrade to 10.6.8 and re-download OS X Yosemite via App Store:
Mac OS X v10.6 Snow Leopard: How to Erase and Install - Apple Support