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

Loner T

Level 9

59,536 points

Nov 13, 2017 3:28 PM in response to amytom12

Please remember to run SMC and NVRAM Reset after you replace the file.

amytom12 Author

Level 1

12 points

Nov 13, 2017 3:31 PM in response to Loner T

Okay, but I'm running into an error. When I try to drag the unedited file into the folder, there is a stop sign.

Loner T

Level 9

59,536 points

Nov 13, 2017 3:33 PM in response to amytom12

You do not have the privileges to replace the system file. You will need to use 'sudo' and use a Terminal to copy the file to the correct destination.

amytom12 Author

Level 1

12 points

Nov 13, 2017 3:37 PM in response to Loner T

May I have the Terminal command for that? I'm also on the Admin account. I'm the only owner of the mac

amytom12 Author

Level 1

12 points

Nov 14, 2017 12:46 PM in response to Loner T

So I just have to copy and paste "sudo codesign -fs - /Applications/Utilities/Boot\ Camp\ Assistant.app" into terminal and it should work? And what is "--deep"?

amytom12 Author

Level 1

12 points

Nov 14, 2017 1:13 PM in response to Loner T

Ok, will do that command. I'll tell you the results.

Loner T

Level 9

59,536 points

Nov 14, 2017 1:28 PM in response to amytom12

Does BC Assistant run correctly? Do you see two options in your BCA tasks list?

amytom12 Author

Level 1

12 points

Nov 14, 2017 1:32 PM in response to Loner T

Nope, I still see 3 options.

amytom12 Author

Level 1

12 points

Nov 14, 2017 2:17 PM in response to Loner T

I can't drag the backup info.plist file because there is still a cross with a circle. Like a stop sign.

amytom12 Author

Level 1

12 points

Nov 14, 2017 3:00 PM in response to Loner T

Okay, I looked up somewhere and they told me to do csrutil disable and it worked. Now I have 2 options but it says has the same error as before. "Windows 10 is not supported on this mac"

Loner T

Level 9

59,536 points

Nov 14, 2017 3:53 PM in response to amytom12

If you insert the DVD, and post the output of diskutil list, we can check if the DVD has any issues that is causing the error.

amytom12 Author

Level 1

12 points

Nov 14, 2017 4:42 PM in response to Loner T

The IR5 one is the DVD with the Windows 8.1 ISO burned onto it.

amytom12 Author

Level 1

12 points

Nov 15, 2017 1:22 PM in response to Loner T

Yes, I do see it.

amytom12 Author

Level 1

12 points

Nov 15, 2017 1:33 PM in response to Loner T

Alright, I'll do that. How can I make an MBR? I got all this done. What do I do next?

amytom12 Author

Level 1

12 points

Nov 15, 2017 1:54 PM in response to Loner T

This is confusing, where do I do all of these steps? What am I even supposed to do? I installed gdisk btw. I'm not on high sierra either.

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