Release the Option key when the Startup Manager screen appears.
Select the USB drive and format it as with a GUID Partition Map . Name the drive YosemiteUSB . Open Terminal (Applications > Utilities). Paste the following command into Terminal and press Enter: mac os x yosemite 1010 5 download dmg link
Look in your folder for "Install OS X Yosemite". 2. Create a Bootable USB Installer (Recommended) Release the Option key when the Startup Manager
Before downloading, ensure your Mac meets these minimum technical specifications: : Running OS X Snow Leopard 10.6.8 or later. Memory : At least 2 GB of RAM . Storage : At least 8 GB of available space . Compatible Models : iMac (Mid 2007 or newer) MacBook (Late 2008 Aluminum, or Early 2009 or newer) MacBook Pro (Mid/Late 2007 or newer) MacBook Air (Late 2008 or newer) Mac mini (Early 2009 or newer) Mac Pro (Early 2008 or newer) 3. How to Install from DMG How to download and install macOS - Apple Support (IN) Open Terminal (Applications > Utilities)
Before installing, verify your Mac meets these minimum technical specifications: How to download and install macOS - Apple Support
Insert your USB flash drive (8 GB or larger).