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Solving OS X problems: Finding old utilities, removing a partition, and migrating data

Glenn Fleishman | July 7, 2015
This week, Glenn answers questions about deauthorizing software, reinstalling AirPort Utility, managing a Fusion drive, and Migration Assistant.

Also note that Apple is retro: the AirPort Extreme Card shown as the graphic on these pages was for sale from about 2003 to 2009 for late-generation PowerPC-based Macs.

Repartitioning a drive to remove a partition

L. Faye Russell had to set up separate Mavericks and Yosemite bootable partitions in order to deal with crashing programs in Yosemite. However, the Mac used a Fusion drive, and that resulted in an issue:

I would like to delete the Mavericks partition and expand the Yosemite partition to encompass the entire internal hard drive (i.e. return my hard drive to a single partition). However, the controls for doing this in Disk Utility are all unavailable.

Normally, if you use the GUID Partition Scheme to format a drive--it's the default format for new Macs--you can create and resize partitions at will. A drive is a physical thing, while partitions are "soft" or "logical," managed by the startup firmware (EFI) and operating system.

But Fusion is a finicky beast. For those who don't have a Fusion drive, it's a combination of fast SSD storage and a slower hard-disk. OS X automatically optimizes storage so that more frequently used files move to the SSD. This gives you some of the advantages of SSD, such as fast startup time, without the expensive of an SSD the size of your entire volume, nor having to manage moving files around yourself or fit the entire OS on your startup SSD volume.

Apple notes you can only create a single partition on a Fusion drive, and Disk Utility places this separate partition exclusively on the hard drive. Once created, Apple offers no advice, nor can I find anyone with advice to offer, on deleting the partition without fully erasing the drive. Since you have a Fusion system, you'd also want to be sure to initialize it via OS X Recovery, which can correctly restore the state.

A recent Mac 911 provides details on cloning and restoring an OS X volume. It's tedious, but it would regain your lost storage.

Migration troubles

Several readers have questions about Migration Assistant.

Mike Imbrogno asks:

I'm trying to restore a Time Machine backup of late 2009 MacBook that was running Yosemite to a mid 2010 MacBook currently running Lion. Should I update the 2010 MacBook to Yosemite first?

I don't believe it's ever possible to use a newer Time Machine backup to restore to an older version of OS X. You might be able to retrieve files and not the entire system, but even then, I'd worry that there would be an incompatibility.

For best results, upgrade to Yosemite first, since it sounds like that's what you're planning. If you intend to wipe the 2010 MacBook for Yosemite, you can then restore from the Time Machine backup during the setup process.


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