Note: This link downloads a file named InstallOSX.dmg . Inside this DMG is a package installer ( InstallOSX.pkg ) that unpacks the actual "Install OS X Yosemite.app" into your Applications folder. 2. The Mac App Store Method
For a safe download, avoid third-party "DMG" links found on search engines, as they often contain adware. Use the official Apple Support link to download the installer App, and use the Terminal command if you require bootable media. mac os x yosemite 1010 5 download dmg link