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whompy

macrumors newbie
Original poster
Dec 5, 2019
5
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I installed Boot Camp on my iMac. Windows 10 worked fine. But now I can't boot up in Mac OS (10.14) anymore. I already tried holding down option while restarting. When I do that, it doesn't give me the option to choose which OS I want, it just starts up Windows.

When I click on "Boot Camp control panel", it asks me which system I want to use to start up my computer, but it only gives me one option: "disk 1 Windows". There is no Mac option. I also tried digging around in some settings, and found where I could select Mac OS X as the startup, but when I selected it, it immediately started up in Windows.

Any idea what I'm doing wrong? Any help would be greatly appreciated!

Thanks!
 
I don't know. I certainly didn't intend to. I don't think I did- check out this screenshot of my disk management thing. My boot camp only takes up about 50 GB. Any ideas?
disk management pic.PNG
 
You may have destroyed your macos partition - just look at Disk 0 partition 2, shows an empty drive at this point (free space = capacity).

On an unrelated note, I think 50GB of space is inadequate for windows, just look at at the free space 12GB. That's too small even to update windows, never mind install applications.
 
Destroyed my macos partition?! That sounds really bad. Is that fixable? In order to use macos again, would I have to re-download macos? Thanks for responding earlier!
 
UPDATE: I called the local Mac store, and they suggested that before I bring the computer to them, I should call Apple Care and see if they could help me over the phone.

So I called them, and the first thing they told me to do was to shut down the computer, then restart it while pressing 'option'. Even though I had already tried that 3 or 4 times, I sighed, shut down the Mac, then restarted while holding down 'option'.

Miraculously, it worked this time. I don't know why it didn't work before.

I've now gone back and forth between Windows 10 and Mac several times and have had no problem.
 
I have the same problem and have tried restarting while holding down “option” but I still only get the windows option. Any ideas?
 

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Instead of restarting, try shutting down, then waiting a few seconds. Then press the power button and immediately press option. I think it's difficult to know exactly when to press option when you select "restart" because it's hard to tell when the computer actually turns off and back on.

But when you turn it off completely, then you know when it's off. Then you turn it on and you know exactly when to press option. I think that's why I was able to get mine to work.

Also, some have said that you might have trouble if you're not using a mac keyboard. So, if at all possible, use a Mac keyboard instead of PC keyboard.

Let us know if this helped!
 
Instead of restarting, try shutting down, then waiting a few seconds. Then press the power button and immediately press option. I think it's difficult to know exactly when to press option when you select "restart" because it's hard to tell when the computer actually turns off and back on.

But when you turn it off completely, then you know when it's off. Then you turn it on and you know exactly when to press option. I think that's why I was able to get mine to work.

Also, some have said that you might have trouble if you're not using a mac keyboard. So, if at all possible, use a Mac keyboard instead of PC keyboard.

Let us know if this helped!
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I actually tried shutting down the computer already, and I’m using the Mac keyboard.

Thanks anyways.
 
I have the same problem and have tried restarting while holding down “option” but I still only get the windows option. Any ideas?

There is no macOS partition in your screenshot, so it appears you deleted macOS entirely. When you installed Windows, did you delete or format any partitions in the Windows installer?
 
There is no macOS partition in your screenshot, so it appears you deleted macOS entirely. When you installed Windows, did you delete or format any partitions in the Windows installer?
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I don’t remember but it seems like I did. If I deleted Mac OS entirely what can I do?

Thanks
 
I did a backup before I installed windows but I can’t figure out how to restore it.
 
I did a backup before I installed windows but I can’t figure out how to restore it.

From your screenshot, it looks like you also formatted your Recovery partition. You will need to start your Mac using Internet Recovery to reinstall macOS and restore your backup.

1) If you have any files you need to back up in Windows, do this first. You will be destroying your Windows install.

2) Shut down your Mac. If you are able to plug your Mac into a wired network, do so; WiFi will work, but will be much slower.

3) Power on your Mac and immediately hold the Opt+Cmd+R keys. If you are connected to the Internet by wire, you will see a large spinning globe icon appear on your screen. If you need to connect by WiFi, the system will prompt you for the network name and password first.

Even with a fast Internet connection, your Mac might take a LONG time to start, so be patient.

4) Follow the instructions on this page beginning with step 2:

https://support.apple.com/en-us/HT204904

Be sure to click through the link in that step about erasing your disk. You must delete all partitions on your disk and create one partition that fills the entire disk using APFS format. Then you can reinstall macOS.

Later in the install process, you will be prompted to transfer your information. DO NOT SKIP THIS STEP. This will be when you connect your Time Machine backup drive and import your backup. Your Mac will be just as good as new when you’re finished.

If you wish to install Boot Camp again, follow the instructions for doing so here:

https://support.apple.com/en-us/HT201468

Please be very careful. The Boot Camp installer will create the Bootcamp partition for you. When installing Windows, you should only format the partition labeled “Bootcamp” and should not need to create or delete any partitions yourself. When you installed Windows last time, you deleted and/or formatted every partition on your Mac and erased everything. You are very lucky you made a backup or everything you had on your system would be gone forever.

Report back on how it goes for you or if you run into problems.
 
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I’m trying to reinstall macOS but it says bootcamp is locked. How can I unlock it?
 

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I’m trying to reinstall macOS but it says bootcamp is locked. How can I unlock it?

You can't install to that disk because it's not a macOS formatted drive. You must run Disk Utility from the first screen you see in the installer and erase the drive.

As I wrote in my post above:

4) Follow the instructions on this page beginning with step 2:

https://support.apple.com/en-us/HT204904

Be sure to click through the link in that step about erasing your disk. You must delete all partitions on your disk and create one partition that fills the entire disk using APFS format. Then you can reinstall macOS.
 
I was able to reinstall to reinstall macOS following the steps you provided.

Thank you for your help Soba!
 
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So I was able to reinstall macOS but when I trie to update to iTunes 12.4.3 I get error 102.

My Mac air is slow and I’m trying to update macOS 10.8.5 to the latest version but can’t.

Anyone has any feedback?

Thanks
 
So I was able to reinstall macOS but when I trie to update to iTunes 12.4.3 I get error 102.

[...]

Anyone has any feedback?

Thanks

The "error 102" is not a problem with your Mac; I received this error the other day when updating an older Mac. You can download this version of iTunes and install it manually to work around the problem:


My Mac air is slow and I’m trying to update macOS 10.8.5 to the latest version but can’t.

What happens when you try to update it?
 
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