If the system was upgraded from Mac OS X v10.6 Snow Leopard to Lion, the external recovery drive can be used with other systems that were upgraded from Snow Leopard to Lion.” Once again, the 2011 Macs that ship with Lion represent a special case.Īpple states: “If the computer shipped with Lion, the external recovery drive (created by Disk Assistant) can only be used with the system that created it. Creating a Recovery HD partition via Disk Assistant may also fail if you have FileVault enabled at the time. Make sure you create this external drive before disaster strikes, as Disk Assistant requires access to a functional Lion drive with a Recovery HD partition. After booting from Recovery HD on this external drive, you can repair, erase, repartition, and/or reinstall Mac OS X on your internal drive. Use it to set up a flash drive (or other USB drive) with a Recovery HD partition on it. One way to accomplish this is via Apple’s If this advice is coming too late, you can redownload a copy from the Mac App Store (by holding down the Option key when selecting the Purchases tab). If you plan to use it again, save the application before it gets deleted. One complication here is that the Install OS X utility is moved to the Trash as part of an update/install to Lion.

To do this, you’ll need a copy of the Install Mac OS X utility from the Mac App Store. If you want to reinstall Lion without the need for an Internet connection, you have two main alternatives.īootable Lion install disc. Reinstalling OS X 10.7 via Recovery HD requires an Internet connection, as the installer has to both download OS X software and verify your computer’s eligibility. In such cases, you’ll have to rely on the Recovery HD option to reinstall Lion. These Macs have their own separate version. The version of Install OS X Lion available from the Mac App Store will not install Lion on these Macs.

To do this, you again start up from the Recovery HD partition and go directly to the Reinstall Mac OS X option.Īll of this gets still more complicated if you have one of the new Macs that come with OS X Lion preinstalled (the 2011 MacBook Air and Mac mini). If you are only concerned about corrupt system files, you may be able to skip a restore of your data and just reinstall Lion.

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