This is a pre-release update to OS X v10.11. If you have OS X v10.11 installed, download this update by clicking Updates in the toolbar of the Mac App Store. If you do not have OS X 10.11 installed, use your download code on the Mac App Store to get started.
• Devices running iOS 9 Beta may not connect to iTunes on OS X El Capitan Developer Beta 4. To resolve install Xcode 7 beta or iTunes 12.2 or later.
• Xcode 6.x has known compatibility issues when run on OS X El Capitan. It is strongly encouraged that you use Xcode 7 when running on OS X El Capitan.
• AIM video chat and screen sharing in Messages are not available in this beta.
• Faces may not be detected in newly-imported photos.
• Email received before installing OS X El Capitan Beta 1 will not work with the Proactive Assistant features.
• The share menu may not create new Mail compose windows when used with some apps.
• Lifting and Stamping adjustments in Aperture may cause the app to unexpectedly exit.
• The Mail app may not be visible after reboot. To work around, quit the app and relaunch.
• iCloud Keychain will not sync passwords & credit cards with previous versions of iOS 9 and OS X El Capitan Beta.
• Some full screen metal applications may not update reliably. Running the application in a windowed mode may resolve the problem.
• Flash Player 220.127.116.11 does not work with Safari’s tab audio feature.
Developers can get a download code for El Capitan from the link below...