Trouble with changing 600GB to 1TB

Welcome to the Apple Support Communities.

If you did not follow these steps to remove the Windows Boot Camp partition, Remove Windows from your Mac using Boot Camp - Apple Support, then you must erase your entire startup disk to reclaim the storage space.

However, since this will erase all data, you need a backup. If you do not already have a Time Machine backup drive, here’s an excellent one sold by Apple: G-Technology 4TB G-DRIVE mobile USB-C Portable Hard Drive - Apple. You can then follow the steps in this Apple Support article to setup your Time Machine backup: Back up your Mac with Time Machine - Apple Support. After a successful backup, you can erase your Mac.

Shut down your Mac, then startup into Internet Recovery Mode (Option-Command-R) by immediately pressing and holding those keys at startup. Then, Use Disk Utility to erase an Intel-based Mac - Apple Support. When in Disk Utility to erase your startup disk, select "View" > "Show All Devices" to erase the main SSD (its name will end in "Media"). After erasing your startup disk, reinstall macOS: How to reinstall macOS - Apple Support.

After erasing your Mac and reinstalling macOS, you will be presented with a Setup Assistant. Set up your Mac again and restore from your Time Machine backup: Restore your Mac from a backup - Apple Support. 

Jack

Thanks for that info! It looks like your Mac forgot where to start up from, or it was unable to locate your startup volume. Try these steps to resolve the issue.

Prepare - open Disk Utility

1. Start up from macOS Recovery: Hold down Command-R as you power on or restart your Mac. Release the keys then the Apple logo and a progress bar appear, or when a spinning globe appears. In the latter case, you will need to connect to a Wi-Fi network to download macOS Recovery from the Internet.
2. If you're prompted for an administrator password, enter it to continue.
3. From the list of utilities, select Disk Utility and click Continue.
4. Click the View button, then select Show All Devices.
5. If you see an icon looking like a stack of paper next to "Macintosh HD", click the arrow next to that entry to expand it. It should reveal two volumes inside.
6. Select Macintosh HD. If a Mount button appears, click on it. It should change to Unmount.
7. Select Macintosh HD - Data. If a Mount button appears, click on it. It should change to Unmount. You might be prompted for your login password; enter it to continue.

Check the disk for errors

1. Select the APFS Container entry just below the Apple SSD. Then, click the First Aid button to examine the container, along with all APFS volumes inside. This includes your startup volumes.
2. If First Aid comes back clean (no errors or everything resolved), proceed to the next step. If First Aid fails, reveal the repair log and please post the error here.
3. Select the Apple SSD entry at the top of the window, and run First Aid on that.
4. If First Aid comes back clean (no errors or everything resolved), proceed to the next section. If First Aid fails, reveal the repair log and please post the error here.

Give the free space to your APFS container

When Boot Camp Assistant deletes Windows, it first removes the Windows partition (which was successful), and then grows the startup container back to full size (failed). To manually grow the APFS container to the full size of the disk, complete these steps.

1. Select the Apple SSD entry at the top of the window.
2. Click Partition. If you're prompted to add a volume instead, click Partition to confirm your intent.
3. There should be a 400 GB slice marked as Free Space. Select this entry, then click (-) to "delete" it. The slice containing the APFS Container should then encompass the entire drive. Click Apply to apply the changes.
4. If successful, Disk Utility shouldn't report any errors. If Disk Utility does report any errors, please stop and post the error(s) here.

Attempt to start up normally

Now that First Aid has been run and the free space has been returned, try starting up your Mac normally:

1. Quit Disk Utility.
2. At the top left corner of the screen, click the Apple logo, then select Startup Disk.
3. Select Macintosh HD as the startup disk, then click Restart.

If Macintosh HD doesn't appear as a valid startup disk, you will likely need to reinstall macOS (without erasing your data). Quit the Startup Disk app, then select Reinstall macOS and follow the onscreen instructions.

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I'll post the steps to remove the Windows boot files separately; otherwise I would have broken the character count limit :)

YenKooy wrote:

Mounted them both. And did the First Aid step, my laptop just went blackout after running for a few minutes. Showing a folder icon with question mark in it and a support url at the bottom.

:(

Unfortunately, it appears that your filesystem got corrupted when Boot Camp Assistant failed to remove Windows. I'm guessing something went wrong while the APFS container was being resized, and one of the structures in your startup volumes got damaged. I was hoping that the container and its volumes were undamaged and could be resized easily.

At this point, Jack is right: you're best off erasing your Mac and starting clean with a fresh filesystem. I don't know of any remedies to fix an issue that causes First Aid to kernel panic (crash and reboot/shutdown). Any further attempts to repair the situation would likely be experimental at this point.

If you already have a Time Machine backup, follow Jack's steps to erase your Mac and reinstall macOS. You can then restore from your backup in the Setup Assistant.

If you don't have a Time Machine backup, please let me know. There are a couple of options to try recovering your data, and you will need a sufficiently large external drive for all of them:

• Low-level disk duplication: This creates a perfect copy of the internal drive and puts it onto an external drive. Once that's done, you would erase your Mac, reinstall macOS, and then attempt to import your data from the clone. In this scenario, the external drive should be the same size as your internal drive (exactly 1 TB large). The cloning process would take a long time to complete.

• Run macOS on an external drive: For this option, you would connect an external drive (1 TB or larger), erase it, install macOS onto it, and then attempt to import your data from the internal drive. If successful, you would then erase your internal drive, reinstall macOS, and then import your data from the external drive. This option is the safest one for self-service, as no Terminal commands are needed.

• A third-party data recovery service: Extremely expensive, but should be able to recover the data.

Please do NOT attempt to reinstall macOS on the internal drive without erasing your data. At this point, writing more data to the startup volumes would likely just corrupt them further.

Jack-19 wrote:

Welcome to the Apple Support Communities.

If you did not follow these steps to remove the Windows Boot Camp partition, Remove Windows from your Mac using Boot Camp - Apple Support, then you must erase your entire startup disk to reclaim the storage space.

I don't think that's actually the case.

When Boot Camp Assistant removes the Windows partition, it performs three operations (as far as I'm aware):

1. Delete the Windows partition
2. Give the space it occupied back to macOS (grow the parent APFS container to occupy that space)
3. Delete the Windows bootloader in the EFI partition

If Boot Camp Assistant fails to remove Windows, I've been able to complete those steps using Disk Utility (for steps 1-2, use the Partition button) and Terminal + Finder for step 3 (Terminal to mount the EFI partition, Finder to delete the bootloader and unmount the EFI partition).

While a full-disk erase would indeed be guaranteed to remove Windows, it seems to be an unnecessary hassle in this case (I think).

EDIT: Saw the warning in the linked Apple Support article. I can understand why Apple would put that warning there (since it's easy to leave the bootloader behind), but once the bootloader is gone, Windows should no longer appear in Startup Manager (hold Option while rebooting).

YenKooy wrote:

I did erase and install MacOS according to Jack’s instruction. And now my laptop is showing the black screen with same icon folder with support url. I tried to hold on to the power button 10 seconds to make it sleeps. Then press the power button to start again, it shows the same black screen. Looks like I need to visit apple physical store for a physical check up 😰

o.O

Just to confirm, what options did you use when you tried to erase the top level of the SSD? Choose these options to ensure that macOS installs properly:

Name: Anything you want, but the default is Macintosh HD

Format: APFS

Scheme: GUID Partition Table/Map

If macOS still fails to install, unfortunately the actual cause could be a physical drive failure :(

To check your hardware, try running Apple Diagnostics from the Internet: hold down Option-D as you power on or restart your Intel-based Mac. Choose a language and a privacy option when prompted to start the test. Note and check the error code(s) shown: Apple Diagnostics reference codes - Apple Support (CA) Also, check the SMART status of the SSD in Disk Utility (in macOS Recovery).

If you have a Time Machine backup, your data should be ok. If you don't, you'll want to take your Mac in to a professional data recovery service.

Delete the Windows boot files

Windows stores certain pre-boot files in the hidden EFI partition so that it can start up normally. These files include the bootloader for Windows Boot Manager, as well as other files, such as the BCD file used to describe the internal drive for Windows. When your Mac starts up, it detects these files and provides the option to boot Windows when you use Startup Manager (hold down Option as you restart).

Normally, when Boot Camp Assistant removes Windows, it deletes these files as part of the process. Unfortunately, since it failed, we will need to do this manually. Note that the EFI partition should be preserved (some Apple-provided firmware is stored here on Intel-based Macs), but the Windows files inside it should be removed. To remove the Windows boot files:

1. Start up in macOS and log in to an administrator account.
2. Eject and disconnect all external drives.
3. Open Terminal, located in Applications -> Utilities.
4. Run this command to mount the hidden EFI partition: sudo diskutil mount EFI
5. Enter your administrator password when prompted. Terminal won't show any characters or indication as you type your password.
6. If successful, diskutil should report that the EFI partition was successfully mounted. You can now quit Terminal.
7. Open a new Finder window, and select the EFI partition in the sidebar.
8. On the root of the EFI partition, you should see a folder named EFI. Open it.
9. Inside the EFI folder, you should see three folders (shown below):
   1. APPLE: Leave this folder alone. It contains Mac firmware.
   2. Boot: Delete this folder. It contains a Windows bootloader (bootx64.efi).
   3. Microsoft: Delete this folder. It contains Windows startup files, including the Windows Boot Manager and BCD file.
10. When done, "eject" the EFI partition in the Finder to unmount it.

To test whether the operation was successful, restart your Mac while holding down the Option key. The only option that should appear is Macintosh HD (not Windows).

Hi Yen,

Absolutely not. You can remove Windows without having to erase your entire Mac.

Please complete these steps to describe the layout of your internal drive. Once that's done, I can post the steps on how to remove the Windows partition, and give its space back to macOS:

1. Start up in macOS and log in.
2. Open Terminal, located in Applications -> Utilities.
3. Type this command and hit Enter (Return): diskutil list
4. Post the output here.

Encryptor5000 wrote:

Jack-19 wrote:

Welcome to the Apple Support Communities.

If you did not follow these steps to remove the Windows Boot Camp partition, Remove Windows from your Mac using Boot Camp - Apple Support, then you must erase your entire startup disk to reclaim the storage space.

1. I don't think that's actually the case.

When Boot Camp Assistant removes the Windows partition, it performs three operations (as far as I'm aware):

Delete the Windows partition

2. Give the space it occupied back to macOS (grow the parent APFS container to occupy that space)

3. Delete the Windows bootloader in the EFI partition

If Boot Camp Assistant fails to remove Windows, I've been able to complete those steps using Disk Utility (for steps 1-2, use the Partition button) and Terminal + Finder for step 3 (Terminal to mount the EFI partition, Finder to delete the bootloader and unmount the EFI partition).

While a full-disk erase would indeed be guaranteed to remove Windows, it seems to be an unnecessary hassle in this case (I think).

EDIT: Saw the warning in the linked Apple Support article. I can understand why Apple would put that warning there (since it's easy to leave the bootloader behind), but once the bootloader is gone, Windows should no longer appear in Startup Manager (hold Option while rebooting).

The full erase is usually necessary to remove all the Windows files and not cause great damage to your macOS installation.

Erasing volumes using the

diskutil list

Command as a guide can be very risky and a small mistake can erase macOS or even your Recovery partition. For most users, although time consuming, it is easier and far less risky to do the erase than to attempt to modify the file stricture and partitions.

Just my opinion.

Jack

Thanks for that!

For the black screen at startup, what icon does it show?

It looks like the Windows partition was indeed deleted, but the free space wasn’t returned to the APFS container containing your startup volume. I’ll be at my Mac in about an hour and will post the steps needed to reclaim the free space. In the meanwhile, try running First Aid in Disk Utility.

Just to confirm, did you check that Macintosh HD and Macintosh HD - Data are mounted? The mounting process also unlocks the volumes, and prompts you for your password if needed.

(steps 5-7 in the first section)

Jack-19 wrote:

The full erase is usually necessary to remove all the Windows files and not cause great damage to your macOS installation.

Erasing volumes using the

diskutil list

Command as a guide can be very risky and a small mistake can erase macOS or even your Recovery partition. For most users, although time consuming, it is easier and far less risky to do the erase than to attempt to modify the file stricture and partitions.

Just my opinion.

Jack

Erasing stuff through Terminal can definitely be risky - I usually just use "diskutil list" or some variant of that to see how exactly a disk is configured. I do most of my actual disk operations in the Disk Utility GUI since it's safer (it hides all of the critical/special volumes, and automatically performs First-Aid checks before partitioning).

Regarding the Windows files, the only places that I know of where Windows files get stored would be in these areas:

• On the EFI partition stored on the internal drive,
• In the BOOTCAMP partition (formatted as NTFS by Windows),
• If applicable, the separate Windows Recovery partition, and
• In the temporary OSXRESERVED partition (formatted as MS-DOS FAT).

All of these locations are completely isolated from the macOS files stored in the APFS container (the container is itself a partition, separate from the four above). I think the main risk is messing with the EFI partition contents and accidentally deleting the wrong files (since some Apple firmware is stored there) but Internet Recovery should still work as expected. If it didn't, most full-drive erases would instantly render a Mac unbootable if it restarts before installing macOS (since a full drive erase deletes all partitions, including EFI).

Mount them both, and then try First Aid on the container again :)