Mac el capitan update stuck at startup
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MAC EL CAPITAN UPDATE STUCK AT STARTUP INSTALL
The install should work now unless there is an issue with the download server at Microsoft. They will either shutdown or freeze that action, thus interfering with the installation. It is by nature that Virus detectors can construe the act of installing software as some Virus activity. Enterprise administrators: Download from Apple, not a locally hosted software-update server. If you have anything such as a Virus detector running it will turn them off. Download on a Mac that is using macOS Sierra 10.12.5 or later, or OS X El Capitan 10.11.6. * In addition to "Repairing Permissions" (if using El Capitan), It cleans out Cache Files and reorganizing Logs (called running a "CRON" procedure), it turns off all third party extensions, plugins, control panels and, System Preferences. Sign in using the password you use to install software. Try quitting all applications and, restart in "Safe-Mode". Click on the Apple icon > About This Mac >Storage to check the space available on your Mac computer. Renewing the Lease is equivalent to giving Smelling salts to someone passed out. Open App Store and update your apps while in Safe mode. Sometimes the Modem forgets its connection and Try going to Network Preferences → Advanced → TCP/IP and click on Renew Lease.
② If the above doesn't make a difference.
Let’s look at solutions to fix macOS Sierra reboot loop issues. This does prevent the macOS Sierra from booting normally. Or, the 3rd party kexts and extensions in the OS X (El Capitan, for instance) that you upgrade over can not be called. ① How long are you waiting? Try again and wait about another minute. Sometimes, if your connection from your ISP is slow, you may need to wait longer. First, the macOS Sierra installation has not processed correctly.