Level 1

12 points

No sound on 27 inch iMac Mid 2011 running Windows 8.1 on Botcamp

Hello! I just installed 8.1 on my Mac and everything went very well. Then only issue I found is the sound and the brightness. I try to turn down the brightness but nothing happens. The bar shows that it's going down but it isn't. The sound is also broken. When I try to turn up the sound, there is a circle with a cross with the volume icon. I tried many things to fix the sound issue. I tried downloading new drivers, updating drivers, etc. The brightness issue, I don't really care but it would be useful if we can fix it too. I talked to Microsoft about the sound problem and they said the only way to fix it is to get Windows 10. Unfortunately, my mid 2011 Mac does not support Windows 10 on boot camp. I'm in desperate need of the sound in windows so I need your help! Thanks!

Posted on Oct 15, 2017 8:28 PM

Top-ranking reply

Loner T

Level 9

59,536 points

Posted on Oct 16, 2017 5:46 PM

Does your built-in Optical drive function properly?

amytom12 wrote:

And oh, I forgot to mention. When I was installing Windows 8.1, I got a MBR table error and something about EFI's and GPT. I looked on YouTube and this guy said to go to terminal on my mac side and put some codes in. I don't know if this effects the sound.

Yes, it does. If you do not use the internal Optical drive and a DVD (or CD) to install Windows on your specific model and instead use a USB (or manually choose) EFI boot, the Audio devices are not exposed correctly. This is indicated by the current BIOS Mode being UEFI. On your specific 2011 model, it should be Legacy (or BIOS).

The only method to switch to BIOS mode, is to remove the current installation using Remove Windows from your Mac - Apple Support and then use a DVD in the Optical drive to install W8.1. The 'code' you were asked to input in Terminal removed the MBR, forcing a UEFI installation, and causing the Audio to malfunction.

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152 replies

amytom12 Author

Level 1

12 points

Dec 2, 2017 8:00 AM in response to Loner T

I think I need to make it a manual partition because it says that the disk has a Windows 10 ISO on. It only accepts windows 8.1 or below.

Loner T

Level 9

59,536 points

Dec 2, 2017 8:06 AM in response to amytom12

Since we have done this before, using Disk Utility and GDisk, can you repeat the steps and post back if you see any issues?

amytom12 Author

Level 1

12 points

Dec 2, 2017 8:09 AM in response to Loner T

Okay, I'll try to get a partition to work with GDisk.

amytom12 Author

Level 1

12 points

Dec 2, 2017 8:22 AM in response to Loner T

I did step 1 - 13. Is the output ok? Should I do step 14 and reboot?

Loner T

Level 9

59,536 points

Dec 2, 2017 11:00 AM in response to amytom12

No. Remember we need to first create a fourth partition for Windows using Disk Utility. Notice that Gdisk complained about GPT4.

amytom12 Author

Level 1

12 points

Dec 2, 2017 11:18 AM in response to Loner T

Okay, I made a new 220 GB MS-DOS (Fat) partition and now it doesn't complain about GPT 4

What do I do now? Reboot?

Loner T

Level 9

59,536 points

Dec 2, 2017 11:41 AM in response to amytom12

You need to use some default values, instead of typing 'N' or 'Y'. For example the MBR Hexcode should be the default as shown by the utility, instead of typing 'N'.

amytom12 Author

Level 1

12 points

Dec 2, 2017 11:49 AM in response to Loner T

Like this?

For example, for partition #2, I put AF as the Hex code. And for number 3, I put AB.

Loner T

Level 9

59,536 points

Dec 2, 2017 11:54 AM in response to amytom12

Since you use the same values as defaults, please continue.

amytom12 Author

Level 1

12 points

Dec 2, 2017 11:58 AM in response to Loner T

Alright, so now just reboot my mac?

amytom12 Author

Level 1

12 points

Dec 2, 2017 1:37 PM in response to Loner T

And to quit out of terminal, do I just force quit it or use a command to quit terminal?

Loner T

Level 9

59,536 points

Dec 2, 2017 2:53 PM in response to amytom12

A Reboot will also close the terminal.

amytom12 Author

Level 1

12 points

Dec 2, 2017 2:58 PM in response to Loner T

Okay, I'm going to reboot my mac.

amytom12 Author

Level 1

12 points

Dec 2, 2017 3:02 PM in response to Loner T

Okay, I saved the progress and rebooted. Now, what do I do?

Loner T

Level 9

59,536 points

Dec 2, 2017 3:20 PM in response to amytom12

Insert your W8.1 DVD, and reboot your Mac and hold Alt/Option key. From the visible DVD icons select the one that is called Windows. Do not choose anything else.

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No sound on 27 inch iMac Mid 2011 running Windows 8.1 on Botcamp