Mac experts: Simple question about doing a clean install
June 20, 2015 5:04 PM   Subscribe

My machine has gotten sluggish, and I think I'm going to try a clean install, which it's never had. I understand how to wipe a partition and do a complete install from a bootable USB drive. What I'm not sure about is getting my documents off my backups. Is it as simple as using Migration Assistant?

* Early-2011 13" Macbook Pro
* Mac OS X 10.10.3 Yosemite. Not encrypted.
* Two user accounts (although one could be deleted if need be).
* I have a Boot Camp windows partition
* Looking at the volumes in Disk Utility (with "Show all partitions" enabled), I see: EFI, Mac Daddy, Recovery HD, and BOOTCAMP.

* Have a bootable USB installer ready to go.
* I have current backups using both Time Machine (not encrypted) and SuperDuper.

I don't want to do this only to find I've I'm suddenly denied permissions to my own documents, or something like that. Is this going to be as straightforward as I'm hoping?
posted by Alaska Jack to Computers & Internet (5 answers total) 3 users marked this as a favorite
If you do this to do a "Nuke and Pave" you should NOT restore from Time Machine or a clone.

Here are the steps:
1 Create a bootable USB stick with OSX installer
2 Boot from the USB stick
3 Repartition the HD*
4 Install OSX
5 Create Admin account
6 Create User account
7 Setup iCloud and other cloud services
8 Copy the user files into the new User profile (Documents / Pictures / Music from the 2nd back-up.
9 Install only the most needed apps
10 Run Updates
11 Create new Back-Up

Of course you need at least 2 back-ups of your files. For example Time Machine and a clone on a 2nd drive using Super Duper. Or at least copy your user files on a 2nd external drive..
posted by Mac-Expert at 5:38 PM on June 20, 2015

If this were me I would take this time to bail on the bootcamp partition as well. Unless you under-specced that Mac on RAM I would start looking at virtualizing your secondary OSes. More secure, allows encryption, less annoying (no need to reboot to get to the app you need/want), more flexible (can have Linux, Windows 7/8/10, etc.), snapshots, transferable, booya!

I'd probably do things a bit differently from Mac-Expert, but his advice is good as well.

Mine would be:

1. Create an up-todate time machine backup.
2. Either image off the primary Mac partition or do another time machine backup to another different drive.


3. Boot to internet recovery:
3.1 (Your mac should be new enough for this). Use disk utility to do a clean wipe of your drive and all partitions, noting this will kill all files for all OSes so have your Windows file backed up as well.
4. Do a clean install of the OS (I would use the Apple internet recovery and skip the local USB install, but that's just a preference and access to high speed internet and no data cap).
5. Move User account back over from Time Machine.
6. Reinstall any apps I need.
7. Install a VM an put my preferred Windows and Linux OSes in an image.

I usually blow away the local recovery partition, but looks like you can still create one. These directions may work:

I generally no longer worry about one, since one new macs you have the internet one (if you don't mind the time it takes).
posted by cjorgensen at 6:03 PM on June 20, 2015

Response by poster: ok so first thanks you two. There's something I'm not clear on though.

Mac-Expert says "you should NOT restore from Time Machine or a clone." So, what I'm trying to understand is, why not? Isn't that exactly what Migration Assistant is for? I'm not arguing -- just trying to understand.

(Also, to reassure you, as I mentioned I have two separate back-up drives: one via TM, the other via SuperDuper.
posted by Alaska Jack at 6:35 PM on June 20, 2015

Indeed if you complain about something not running right in your Mac and want to do a clean install than you don't want to import any "crud" from the past. Just a squeaky clean install with only your personal data.
posted by Mac-Expert at 7:00 PM on June 20, 2015

I agree Migration Assistant works great, but if you assume there is a problem I wouldn't use it as it may bring that problem to the new install.

I would wager your slowdown actually is not because something is wrong, but because I'm guessing you have Yosemite installed on a computer with a hard drive (instead of an SSD). Yosemite is super sluggish without an SSD.

Approaching this by figuring out what the problem is would be better than wiping and restoring as you might end up right where you are now (assuming you bring the problem in via Migration Assistant or you're just expecting more performance from Yosemite than it can deliver on a spinning drive. You'll also want at least 20 GB free space on the drive, and 4 GB RAM minimum. 8 is better, and 16 if you're doing heavy lifting with lots of apps. I would be hesitant to drop money (for SSD and RAM) into a 2011 MBP, but if getting a new computer isn't in the cards it could make sense.

Problems with the discoveryd and powerd processes pegging the processor are common on Yosemite. Check Activity Monitor (show 'all processes' instead of 'my processes' and sort by CPU. If discovered is hogging the processor you can restart it with this terminal command:

sudo launchctl unload -w /System/Library/LaunchDaemons/; sudo launchctl load -w /System/Library/LaunchDaemons/

Paste that in and type your computer's password (the cursor won't move so it will look like you aren't typing it, but it will work). discoveryd is supposed to go away in 10.10.4 so this may get better soon. I have to do this a few times a week.

You can keep an eye on the processor with Menu Meters but the sound of the fans will also let you know.

I would also check for Adware, verify the disk is good, install uBlock, and turn off Transparency (in System Preferences > Accessibility > Display).

I've got some more tips to eek out performance in anther thread here.

As an experiment before going ahead with this you can install Yosemite on an external drive without importing your data and see how the performance of a fresh install is on your hardware. You'll probably find it similar to what you have and you can boot back to your internal drive with your files and know you aren't missing out on better performance. The drive interface and speed would have to be taken into consideration when comparing it to your existing internal drive.
posted by ridogi at 8:31 PM on June 20, 2015 [4 favorites]

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