Disconnect all wired peripherals except those needed to boot, and remove all aftermarket expansion cards.
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Press and hold the power button until the power shuts off. If there's a built-in optical drive, a disc may be stuck in it.
#Mac hangs on boot from external drive Bluetooth#
The battery level shown in the Bluetooth menu item may not be accurate. If you use a wireless keyboard, trackpad, or mouse, replace or recharge the batteries. Sometimes a boot failure can be resolved by resetting the NVRAM. According to Apple documentation, you need at least 9 GB of available space on the startup volume (as shown in the Finder Info window) for normal operation. The easiest way to deal with the problem is to boot from an external drive, or else to use either of the techniques in Steps 1b and 1c to mount the internal drive and delete some files. If you had previously seen warnings of low disk space, this is almost certainly the case. If the startup process stops at a blank gray screen with no Apple logo or spinning "daisy wheel," then the startup volume may be full.
#Mac hangs on boot from external drive mac#
If the internal drive of the non-working Mac is user-replaceable, remove it and mount it in an external enclosure or drive dock. This technique won't work with USB, Ethernet, Wi-Fi, or Bluetooth.Ĭ. Use the working Mac to copy the data to another drive. If you have access to a working Mac, and both it and the non-working Mac have FireWire or Thunderbolt ports, boot the non-working Mac in target disk mode. Boot into the Recovery partition, or from a local Time Machine backup volume ( option key at startup.) When the OS X Utilities screen appears, launch Disk Utility and follow the instructions in this support article, under “Instructions for backing up to an external hard disk via Disk Utility.”ī.
![mac hangs on boot from external drive mac hangs on boot from external drive](https://i.stack.imgur.com/hHgEO.jpg)
You need an external hard drive to hold the backup data.Ī.
![mac hangs on boot from external drive mac hangs on boot from external drive](https://eclecticlightdotcom.files.wordpress.com/2021/02/bootextdisk01.jpg)
There are several ways to back up a Mac that is unable to boot. If you don't care about the data that has changed since your last backup, you can skip this step. If you want to preserve the contents of the startup drive, and you don't already have at least one current backup, you must try to back up now, before you do anything else. The first step in dealing with a boot failure is to secure your data.