How to fix a drive partition failure while installing Windows through Boot Camp in High Si...

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in macOS
Boot Camp will add a partition on-the-fly to your system drive, but there are some things that can stand in the way of that process. AppleInsider explains how to fix most of the issues preventing you from setting up that partition, if the assistant throws you the failure to partition error.




Pre-step. Get a backup with something other than Time Machine. For this task, we recommend Carbon Copy Cloner, SuperDuper, or ChronoSync to make a fully bootable, fully clone-able backup volume.

We've spoken about Carbon Copy Cloner and ChronoSync in the past. Before we go any further, it might be worth taking a look again.

Disable FileVault

FileVault can, in some cases interfere with the partitioning process. Why, we're not sure, but the best and least destructive, way around it is to turn off Filevault, if it is on. If it isn't, then go to the next step.

Select System Preferences, and click Security and Privacy.




Click on the FileVault tab. Unlock the pane, validate your credentials, and click Turn Off FileVault.




This isn't an immediate process. Decryption of your drive happens when the Mac is awake and plugged in. So, either use your Mac for a few hours doing things other than making a Boot Camp partition, or tell your Mac to never sleep in the Energy Saver control panel and walk away for a while.

Turn off Time Machine, un-associate any backup drives

You've got a backup, right? Don't proceed any further unless you have a backup that doesn't depend on Time Machine.

First, disassociate any backup drives with Time Machine. Select System Preferences, and click Time Machine.




Click Select Disk




Click on the drive being used as your Time Machine backup, and click Remove Disk. The Mac will pop up a dialog asking you to confirm that you want to do so.



Try to use Boot Camp assistant to partition the drive again. Should it still fail, you may need to remove Time Machine local snapshots as well.

Purge Time Machine local snapshots

For the tech saavy, the procedure to do this is different in High Sierra than it used to be. Apple killed a one-step, easy, Terminal process to turn off the feature, and automatically delete all local snapshots.

The procedure is still in the Terminal, though. Open the Terminal.

Enter tmutil thinlocalsnapshots / 9999999999999999

Depending on how many you have, and the speed of your drive, it may take a few moments to eradicate all the snapshots.




The above steps deal with most of the obstacles to a successful Boot Camp Assistant partitioning of your system drive. Once more, try to use Boot Camp Assistant to make the partition.

If all that still doesn't allow the partition to be created, then...

Format your hard drive

If you've gotten this far, we're pretty confident of your ability to do this step. First, make sure you have a backup! Reformat your drive either by booting from your restore clone, or rebooting in recovery mode, and set up an APFS partition for your macOS install, and a macOS Extended (journaled) partition for what will become your Boot Camp partition later in the process.

Restore your backup to the APFS partition, run the Boot Camp Assistant again, and all should be well.

Comments

  • Reply 1 of 10
    emig647emig647 Posts: 2,409member
    I ran into this and none of these methods worked for me. It ended up being related to the size I was choosing. On a 512GB drive selecting 120GB size would result in the posted error. Tried at least a dozen times. 90GB ended up working after I noticed someone else having the same issue. 
    ivanh
  • Reply 2 of 10
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    emig647 said:
    I ran into this and none of these methods worked for me. It ended up being related to the size I was choosing. On a 512GB drive selecting 120GB size would result in the posted error. Tried at least a dozen times. 90GB ended up working after I noticed someone else having the same issue. 
    Given that Boot Camp Assistant really wants contiguous space, I wonder what was locked in those 30GB, from 120GB to 90GB.

    I'll take a gander into what you're talking about. A reformat should have cleared that out as well.
    chia
  • Reply 3 of 10
    What a stupid article. Block-level copies of disk images don't work for High Sierra, so any Super Duper / Carbon Copy cloner image cannot be restored. 

    Obviously this procedure was not tested.
  • Reply 4 of 10
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    6toecat said:
    What a stupid article. Block-level copies of disk images don't work for High Sierra, so any Super Duper / Carbon Copy cloner image cannot be restored. 

    Obviously this procedure was not tested.
    Your assumptions are incorrect. Both Super Duper and CCC -- the tools I use every Monday before the work-week of testing stuff to make a backup -- can do whole-disk bootable images, restore from them, and have been able to do so since October. 

    edited January 2018
  • Reply 5 of 10
    I can vouch for the disk encryption issue, just went through this with a brand new MBP. Once the encryption finished everything worked as advertised.

    There is an app to increase the partition size after you’ve already set up Bootcamp, besides just starting over.
  • Reply 6 of 10
    philboogiephilboogie Posts: 7,438member
    6toecat said:
    What a stupid article. Block-level copies of disk images don't work for High Sierra, so any Super Duper / Carbon Copy cloner image cannot be restored. 

    Obviously this procedure was not tested.
    Your assumptions are incorrect. Both Super Duper and CCC -- the tools I use every Monday before the work-week of testing stuff to make a backup -- can do whole-disk bootable images, restore from them, and have been able to do so since October. 

    I believe the poster is correct here. Statement from Bombich: "Time Machine is a highly proprietary Apple device, and the block-copy tool that CCC uses to clone it is also Apple proprietary."

    https://bombich.com/kb/ccc3/cloning-time-machine-backup

  • Reply 7 of 10
    Mike WuertheleMike Wuerthele Posts: 4,604administrator
    6toecat said:
    What a stupid article. Block-level copies of disk images don't work for High Sierra, so any Super Duper / Carbon Copy cloner image cannot be restored. 

    Obviously this procedure was not tested.
    Your assumptions are incorrect. Both Super Duper and CCC -- the tools I use every Monday before the work-week of testing stuff to make a backup -- can do whole-disk bootable images, restore from them, and have been able to do so since October. 

    I believe the poster is correct here. Statement from Bombich: "Time Machine is a highly proprietary Apple device, and the block-copy tool that CCC uses to clone it is also Apple proprietary."

    https://bombich.com/kb/ccc3/cloning-time-machine-backup

    Read the quote again, we're talking about two different things.

    "Time Machine is a highly proprietary Apple device, and the block-copy tool that CCC uses to clone it is also Apple proprietary."

    1) We're not doing block-copies of a Time Machine backup, we're copying an entire boot volume.
    2) CCC can clone Time Machine anyway.
    3) The link applies to CarbonCopyCloner 3. The current version is CCC5.

    The procedure is tested, and works. On Monday morning, before the work-week of testing random stuff begins, I do a CCC clone of my High Sierra boot volume on this very 2016 MBP with High Sierra. If something goes nutty, or I don't trust something, I restore the backup -- or boot from it to keep working and restore from it when the work day is over.
    edited January 2018
  • Reply 8 of 10
    MacProMacPro Posts: 18,259member
    I hit the EFI failure setting up Boot Camp on a 2012 mac Mini yet a 2013 new Mac Pro ran the installation start to finish automatically.  The difference in Boot Camp installations between various aged Macs is quite large.  Older Macs still requiring the tortuous installation method and now failing and the newer Macs doing it on auto pilot.  I got around the mac Mini's EFI issues by manually deleting the partition and then letting the Windows installation have at it.  This requires using the terminal but it worked like a charm.
  • Reply 9 of 10

    Format your hard drive

    If you've gotten this far, we're pretty confident of your ability to do this step. First, make sure you have a backup! Reformat your drive either by booting from your restore clone, or rebooting in recovery mode, and set up an APFS partition for your macOS install, and a macOS Extended (journaled) partition for what will become your Boot Camp partition later in the process. 

    Restore your backup to the APFS partition, run the Boot Camp Assistant again, and all should be well.

    Can an someone please walk me through this portion?
  • Reply 10 of 10
    OakusOakus Posts: 1member
    I've tried everything on this and it's still giving me the error message. One thing its doing is when im trying to purge snapshots its giving me a message that its a unregonized verb. Am I doing anything wrong? Also its a mid 2011 mac if thats important in any way
    edited June 24
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