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Help! Installed Bootcamp on iMac and now I can no longer access my Mac OS!

Hi ALL,


I'm hoping someone can help... I installed Windows 8 64bit on my 27" iMac and downloaded all recommended drivers. However, now I can only load the Windows partition.


I've tried restarting my computer and have pressed 'option' when restarts and the only harddrive option available is EFI Boot and if I click that it just loads Windows 8.


I've never used Bootcamp before and I'm slightly concerned I have somehow wiped my Mac OS off my computer. As I type I am on Windows Internet Explorer - it's a dark time!


What I'm asking is how do I get my mac hard drive to appear / my mac OS to load back up and not windows? 😟

iMac, OS X Mavericks (10.9.4)

Posted on Sep 10, 2014 2:05 PM

Reply
12 replies

Sep 10, 2014 2:12 PM in response to JodElite

You will need to reinstall OS X:


Reinstall Lion, Mountain Lion, or Mavericks without erasing drive


Boot to the Recovery HD:


Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.


Repair


When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported then click on the Repair Permissions button. When the process is completed, then quit DU and return to the main menu.


Reinstall Lion, Mountain Lion, or Mavericks


OS X Mavericks- Reinstall OS X

OS X Mountain Lion- Reinstall OS X

OS X Lion- Reinstall Mac OS X


Note: You will need an active Internet connection. I suggest using Ethernet

if possible because it is three times faster than wireless.

Sep 10, 2014 4:09 PM in response to JodElite

Yes, it has discs because it came with a special version of Snow Leopard. You cannot use the retail copy of Snow Leopard, so you must use the disc that came with the computer. Here's what you will do:


Drive Partition and Format


1. Boot from your OS X Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.


2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.


3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.


4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.


5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.


6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.


Now, you may have an issue if the drive was formatted using NTFS. OS X cannot write to an NTFS disc. So you will need to first use Disk Utility to reformat the disk to MSDOS (FAT32.) Then you can do the above being sure you change the partition scheme to GUID.

Sep 10, 2014 4:15 PM in response to JodElite

Do you have another Mac? If yes, you can use Target Disk Mode to look at the disk on the iMac. You can start iMac by power-cycling and holding the T key, before the Apple logo appears.


The reverse option is also possible, if you installed Bootcamp drivers, the Boot Camp control panel where you choose to switch has a target disk mode. Also, in the Boot Camp control panel, do you see an OS X selection at all.


Also, if you go into Windows Control panel -> Administrative Tools -> Computer Management and check the Disk Management and see what it has on the disk. You can probably post a screen shot for further options.

Sep 10, 2014 5:06 PM in response to JodElite

1. You have used the entire disk for Windows. If you install all the Bootcamp drivers and use the Control Panel -> Boot Camp, you will see a "Target Disk Mode". There is a very small possibility that you have wiped OS X firmware, but if Bootcamp did things correctly, the Alt key works, but Command+R not working may also be related to not having Recovery HD.


2. If you are willing to wipe the Windows installation, using the Macbook, you can install OS X. What versions are/were running on the Macbook and iMac before Windows was installed on the iMac?


3. Command+Opt+R may work (OS X: About OS X Recovery), if your iMac meets the requirements in Computers that can be upgraded to use OS X Internet Recovery and you have the updated firmware which supports it. I suggest you try Command+Opt+R as a test. If it works check what version of OS X you are offered. Do you have a Time Machine backup on an external drive, which can be used to restore the system?


4. Using the D key during power up may let you access Apple Hardware Test (Using Apple Hardware Test), which can provide iMac hardware details, which can help determine any other options.


5. The other method to find exact model is to look at the back of the iMac and use a magnifying glass to see the exact model. How to identify iMac models

May 14, 2015 7:33 AM in response to Kappy

I have the same problem as JodElite


I tried to restart the computer and tried the COMMAND R and OPTION key thing but my computer just goes to a black screen with a lock and I don't know what the password could possibly be. It is not the same admin. password I had chosen. I can't seem to get back to my mac side. My computer turns on with windows.


Question: Do I reinstall yosemite on my windows side? that was the latest version I had. I am not tech savvy. My imac has no disc slot.

Help! Installed Bootcamp on iMac and now I can no longer access my Mac OS!

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