REVERT to Mavericks

Discussion in 'OS X Yosemite (10.10)' started by sharon22, Oct 19, 2014.

  1. sharon22 macrumors regular

    Oct 19, 2014
    October 19, 2014
    Before upgrading from Mavericks to Yosemite (the "finished version of Yosemite," not the "public beta"), I did a Time Machine backup of my Mavericks.

    For various reasons, I wish to REVERT to my Time Machine Mavericks.

    I have found several methods how to revert, including doing a "clean install" of Mavericks, and then using Migration Assistant to move my stuff from my Time Machine backup into the Clean Install of Mavericks.

    Isn't that overly complicated?

    How about my plan:
    a.) Boot into Recovery Mode ("Command-R") from Recovery Partition
    b.) When the window pops up "To Restore Your Computer Using a Time Machine backup, click Continue."

    Voila! Finished! Right?

    Or.... is there something about the new Yosemite which will not allow me to boot into Recovery Mode from my Recovery Partition? Why are there other methods posted on the Net that are so complicated -- why do a fresh install of Mavericks, then do the migration, etc., that seems complicated and redundant.

    Am I missing something? Or shall I go ahead and boot into Recovery Mode and choose to restore from my Time Machine Backup?

    Thank you!!

    p.s. I know my post is long... I'm just really, really nervous...
  2. seasurfer macrumors 6502a

    Dec 12, 2007
    Why do you want to revert?

    My iMac 2011 27'' was slow when it was running 10.8.5, I upgraded it to 10.9, it got a little better. Yesterday, I upgraded it to 10.10, it is the fastest and smootest since I owned this machine from 2011.

    I got to admit that 10.10 is by far the best Mac OS I used since I started using a Mac in 2003.
  3. sharon22 thread starter macrumors regular

    Oct 19, 2014
    No. I don't "want" to revert... I NEED to revert. Sorry, too many reasons (e.g. job deadlines).

    Anyway... I sure am hoping someone can respond.
  4. BasicGreatGuy Contributor


    Sep 21, 2012
    In the middle of several books.
    Your plan should work.
  5. sharon22 thread starter macrumors regular

    Oct 19, 2014
    BasicGreatGuy, thank you for responding! You are definitely a great guy!

    Just out of curiosity... my plan is so simple: boot into recovery, and restore from Time Machine.

    Why... how come... for what reason has several hours of my Google Searching yielded extremely complex instructions? Like, erase drive, do a clean install of Mavericks, then use Migration Assistant to pull data out of the Time Machine backup, etc.

    I've found lots and lots and lots of people wanting to revert, but I have not found any suggestions that include my "two-step" plan.

    I'm just curious... I guess, well, I think I'm missing something. Sounds too easy?
  6. BasicGreatGuy Contributor


    Sep 21, 2012
    In the middle of several books.
    Your two step plan is used on the forum by many, many people.

    As to the other, a lot of people like doing a clean install, even if nothing bad has happened.

    You are right, though. It can be confusing trying to make sense of a plethora of articles on the web.

    As a whole, the people are very friendly and eager to help one another. Sometimes, it can take a while to get a response, for whatever reason.

    Post back after your plan is done to let us know how it went. It shouldn't take too long, depending on how much 'stuff' you have.
  7. sharon22 thread starter macrumors regular

    Oct 19, 2014
    GreatGuy, Thanks again for your reply! I am now Worried again... :mad:

    You know my "two-step plan".... starting with Booting into the Recovery Partition (Command + R)... well, I just now did some "snooping around" and I mounted my Recovery Partition, and noticed that Yosemite changed some stuff around in it.

    For example, there is a file called "Install Yosemite" in the BaseSystem.dmg file inside the Recovery Partition. :(

    That has me worried that when I boot into my Recovery Partition, it is going to give me Trouble when I want to Restore my Time Machine backup of Mavericks.

    What do you think?
  8. gr8tfly, Oct 19, 2014
    Last edited: Oct 19, 2014

    gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    Not sure what you meant by "... is there something about the new Yosemite which will not allow me to boot into Recovery Mode from my Recovery Partition?", but anyway:

    Starting up with CMD-R should boot into the Recovery HD. From there you should be able to restore from a Time Machine backup. Although there is a Yosemite Recovery HD, I can't think of any reason the backup of Mavericks wouldn't work.

    I would, however, suggest creating a new, single partition on your target drive (GPT, Mac OS Extended (journaled)) before doing the restore (using the Recovery HD Disk Utility). Yosemite creates a Logical Volume using CoreStorage regardless of whether or not the volume is encrypted (FileVault), whereas Mavericks only does so when using FileVault. I don't believe there's any technical reason why Mavericks wouldn't be fine with an unencrypted Logical Volume, but I haven't actually done a recovery myself with one in place. (The engineer in me doesn't like to recommend things without having done it myself or seen evidence convincing me something is correct.) Anyway, this is just something I thought I'd throw out there as I wasn't aware Yosemite did this (use CoreStorage for everything) until I read about it today. Of course, this is all moot if you do use FileVault. :)

    Bottom line, your original plan of just using the Yosemite Recovery HD to do the Time Machine Restore should work fine.

    EDIT: After doing a bit of research, it doesn't look like creating a new single partition can be done using Disk Utility once Yosemite has been installed. That's probably why you're seeing the "complex" instructions floating around. You should be able to do it using a single Terminal command though (use the Info button in Disk Utility with the Yosemite volume selected to get the Disk Identifier - in the example below, "disk1"):

    diskutil cs revert disk1
    Once that completes (it should be just a couple of minutes), you can use Disk Utility like you normally would.


    BaseSystem.dmg is part of how the Recovery HD creates its bootable volume to do new installs. Nothing to worry about - it's been that way since Lion (iirc, that was the first to use Recovery HD).
  9. sharon22 thread starter macrumors regular

    Oct 19, 2014
    Gr8tfly, thank you for your reply!

    But, I don't understand how to do what you said.

    You said to create "a new, single partition on your target drive (GPT, Mac OS Extended journaled)."

    Let's see if I can figure it out: when I'm in Disk Utility, my Internal Drive is already 3 partitions:

    a.) The main partition (mine is called "Macintosh HD")
    b.) EFI partition
    c.) the partition I'll boot into, the "Recovery HD" Partition.

    Do I simply highlight "Macintosh HD" and click on Erase, with the "Extended, Journaled" selected?

    Or, instead of clicking on Erase, do I click on "Partition" and choose One Partition? Won't that zap out the EFI partition?

    I hope I'm making sense :eek:

    I'm just trying to picture in my mind, step-by-step what is *going* to happen, before I actually do it, it's confusing LOL

    What do you think?
  10. gr8tfly macrumors 603


    Oct 29, 2006
    ~119W 34N
    When you create a GPT partition table (say, converting from a PC MBR FAT), the EFI partition is created automatically.

    By new single partition, I mean to select the device (the top level, not "Macintosh HD", the go to the Partition tab. Click on the popup menu that should say "current partition" and set it to "1 Partition". Next, click the Option... button and make sure the GPT partition scheme is selected. That's essentially erases all previous partitions and sets up a single Apple_HFS partition, in addition to the GPT table itself and the EFI. You would then end up with 4 partitions (I assume you're using "diskutil list"), with the HFS partition being the fourth.

    That's all well and good, except for what I learned earlier (and added to my previous post) about Yosemite creation a CoreImage partition and Logical Volume. In that case, it appears Disk Utility is not capable of repartiting a disk using the GUI interface (most of the partitioning controls are disabled). To start from scratch, you will need to use the Terminal command to revert CoreImage to an HFS partition. I believe (and I haven't tried myself) that restoring Mavericks to the Logical Partition should work fine, and you won't have to worry about the terminal diskutil command or whether it's CoreImage or not.

    At a minimum (leaving the Logical Partition as is) you should use the Erase tab and clear the Yosemite install and data.

    The Recovery HD partition is always created automatically when installing OS X, using if Disk Utility Restore to restore OS X, or using the Recovery HD restore from a Time Machine. If one already exists, it will be updated if necessary (Yosemite will update it to 10.10), and also move it to always follow the partition containing OS X.

    Hope this info clears thing up (and I hope I didn't get too detailed.

    I wanted to add a couple of observations I made regarding when/if Yosemite creates a CoreImage partition.

    In one case, I started with a single partition containing Mavericks. I then upgraded to Yosemite. It converted the Apple_HFS partition to CoreImage. Next, I used Disk Utility to add a new partition (shrinking the Logical Volume). This ended up shrinking the CoreImage partition and adding an Apple_HFS partition for the new one (5 partitions total - GPT, EFI, CoreImage, Recovery HD, and Apple_HFS).

    In the other, I started with a single empty HFS partition and created a bootable Yosemite Install partition (using the command-line install app createinstallmedia tool). I then booted to this install partition and installed Yosemite in the remaining HFS partition. This time, no CoreImage partition was created, and I ended up with the two Apple_HFS partitions, with the new Yosemite install followed by a Recovery HD partition. I suspect it did this because of a pre-existing Apple_HFS partition (also, this was the first partition).

    Anyway, I'm sure there are those out there who have more info on how and perhaps why Yosemite installs do what they do regarding CoreImage, and to be sure, I'll be on the look out for it.

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