How to fix "No bootable device, insert boot disk and press enter" ?

Question

Level 1

4 points

How to fix "No bootable device, insert boot disk and press enter" ?

I tried to use Boot Camp Assistant to install Windows 7 to my Mac mini (mid-2011, i5 2.3Ghz, with most updated OS X Yosemite), and the Boot Camp Assistant formatted my USB drive and copied the ISO image of Windows 7 into it successfully. However, when the Mac mini automatically rebooted, it showed the message "No bootable device, insert boot disk and press enter". I tried to switch off the mac mini and hold down the alt/option button when I turned on it again, but no any menu appeared (only the same error message was displayed).

I also did some research on internet and found some experts indicated that the USB drive is using MBR (for old BIOS) rather than GPT, and UEFI only recognizes GPT, so it isn't bootable. Is that exactly the problem? The USB drive was formatted by Boot Camp Assistant actually, why would this happen?

Now I don't know how to fix this problem. I cannot boot into OS X now. Anyone can help?

Mac mini, OS X Yosemite (10.10.3), mid-2011, i5 2.3Ghz

Posted on Jun 13, 2015 10:17 PM

Reply

Answer 1

Top-ranking reply

SunnyLau175 Author

Level 1

4 points

Jun 13, 2015 10:53 PM in response to Loner T

I tried all 4 USB ports and the error message "no bootable device, insert boot disk and press any key" still occurred.

I also checked the USB drive on other Windows PC and found the files can be read properly. It doesn't seem corrupted. If it is really corrupted, how can I solve the problem? At least I want to know how I can get back to the OS X.

Reply

Answer 2

SunnyLau175 Author

Level 1

4 points

Jun 18, 2015 8:15 AM in response to Loner T

Thank you very much. I can boot into Internet Recovery by pressing Command+Opt+R.

After I selected the startup disk again from file menu in the OS X Recovery System, I can boot into OS X now.

but now I don't dare to install Windows 7 in my mac...

By the way, my keyboard is Microsoft digital media keyboard 3000, connected to mac mini via KVM.

Reply

Answer 3

Loner T

Level 9

59,513 points

Jun 14, 2015 5:09 AM in response to SunnyLau175

Can you check if the USB is a USB2 device? Here is an example of a USB2 device.

In some cases, switching to a different brand also seems to address the issue.

Reply

Answer 4

Loner T

Level 9

59,513 points

Jun 13, 2015 10:30 PM in response to SunnyLau175

It is not the USB using a MBR vs GPT. The reference is to the partitioning of the internal disk which is the destination for Windows installation. Mac models prior to Late 2013 models will use MBR for the destination disk. Later models can use either method.

If you see a No bootable device error, either you are using a USB3 flash drive or your ISO/DVD source for Windows is corrupt. In some rare cases, the rightmost USB port in the back of the Mini when facing the Mini works, but others may not. (This usually requires an SMC Reset).

If the issue was MBR v GPT, the Windows installer would need to start properly, and after you picked the designated partition, the MBR v GPT error would be shown by the Windows Installer. You are not able to start the installer.

Reply

Answer 5

Loner T

Level 9

59,513 points

Jun 19, 2015 6:36 AM in response to SunnyLau175

This is expected behavior. You Mini supports booting from either an external Optical drive or a USB drive that BCA creates. It may be an issue with you USB being a USB3 not a USB2 device or the brand of the device. I have used a USB boot on both of my Mid 2011 Minis. I specifically bought SanDisk Cruzer USB2 flash drives for this purpose.

Apple rewrote the Bootcamp 5.1 linked article in this image, but used to explicitly document what models would support both options.

.

Reply

Answer 6

SunnyLau175 Author

Level 1

4 points

Jun 19, 2015 8:05 AM in response to Loner T

My bootcamp version is 5.1.2

I have an external optical drive, and a partition that bootcamp assistant created. Can I just use the external optical drive with Windows 7 DVD to start installation?

I might not prefer buying a new USB drive because it functions properly in normal use.

Reply

Answer 7

SunnyLau175 Author

Level 1

4 points

Jun 20, 2015 9:53 PM in response to Loner T

Thank you. I have successfully installed Windows 7.

I tried the following steps:

1. bought a new SanDisk Cruzer USB flash drive

2. formatted USB flash drive as Mac OS Extended (Journaled) with GUID Partition Table by using Disk Utility

3. ran Boot Camp Assistant to remove previous BOOTCAMP partition

4. used another Windows PC to make ISO image from my DVD again

5. ran Boot Camp Assistant again to start making USB boot drive, partitioning and installation

(Boot Camp Assistant formatted my USB flash drive again as FAT32 with MBR ......🙂)

6. ran Windows Installer from my USB flash drive successfully when my Mac Mini automatically rebooted

7. used Startup Manager (by pressing Alt/Option on start up) to choose booting from BOOTCAMP partition when the Windows Installer finished an initial installation and auto-restarted my Mac

(I found that I cannot show Startup Manager before because of my KVM. When I plugged my keyboard directly to my Mac Mini without KVM, the Alt/Option button worked again when I pressed it on start up ......🙂)

8. finally installed Boot Camp and the attached drivers manually from my USB flash drive into my Windows 7.

I still had to use Startup Manager to boot into Windows every time until I installed Boot Camp driver.

Thanks very much for your help. I might not be confident to try again without your suggestions and comments.

Reply

Answer 8

Loner T

Level 9

59,513 points

Jun 14, 2015 9:33 AM in response to SunnyLau175

Can you try the following to see if you can get back to OS X? If your partitioning has corrupted OS X, you may have to restore from a back up?

Resetting the System Management Controller (SMC) on your Mac - Apple Support

How to Reset NVRAM on your Mac - Apple Support

Reply

Answer 9

Loner T

Level 9

59,513 points

Jun 19, 2015 8:24 PM in response to SunnyLau175

1. You do not want to power-cycle and use Alt key to select the W7 DVD under normal circumstances. This prevents the BC drivers from being loaded which are on the USB. Since your USB drive is not working, I suggest you use a wired keyboard/mouse. The BT drivers are unavailable to support wireless keyboard/mouse. You may get stuck on a black screen. If you use this method, do not select the EFI boot selection, if it does show up. Select Windows and test.

2. The other method is to run BCA, remove the current partition, connect the Optical drive, connect a USB flash drive, and start from the beginning and go through the download drivers and partitioning parts. This is more likely to succeed.

The switching between the two OSes is much simpler if you have BC drivers installed on Windows side. OSX System Preferences -> Startup Disk and Windows Control Panel -> Boot Camp options allow you to switch back and forth. Please also see Boot Camp: Set the default operating system .

Reply

Answer 10

Loner T

Level 9

59,513 points

Jun 18, 2015 9:49 AM in response to SunnyLau175

Do you already have Windows installed?

Reply

Answer 11

Loner T

Level 9

59,513 points

Jun 19, 2015 8:14 AM in response to SunnyLau175

Yes, you can try the external Optical drive. Is it an Apple SuperDrive? I have seen issues with non-Apple Optical drives in the past.

Reply

Answer 12

SunnyLau175 Author

Level 1

4 points

Jun 16, 2015 7:50 AM in response to Loner T

I tried:

1. unplugged power cable for over 15 seconds

2. plugged power cable for over 5 seconds

3. pressed power button and immediately held command + option(alt) + p + r

but the mac mini didn't restart again, and I also didn't hear second startup sound. Only the same blank screen appeared.

Reply

Answer 13

SunnyLau175 Author

Level 1

4 points

Jun 19, 2015 7:43 PM in response to Loner T

No, it is non-apple optical drive, but I can use it in Finder ordinarily.

If I directly use Windows DVD to start installation, does it still have option to let me choose booting between OS X and Windows?

Reply

Answer 14

SunnyLau175 Author

Level 1

4 points

Jun 14, 2015 7:42 AM in response to Loner T

Because I cannot boot into OS X, I used another Windows 8 PC to test my USB drive. The results show that the USB version is 2.0, and data reading is normal.

Reply

Answer 15

SunnyLau175 Author

Level 1

4 points

Jun 14, 2015 8:07 AM in response to Loner T

I unplugged the power cable for several hours, and then plugged it again and tried to hold Alt key and press power button. But it only showed the blank screen and flashed a ? icon.

Reply