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 14, 2017 4:55 PM in response to amytom12

Can you post the output of

diskutil info disk1

Loner T

Level 9

59,536 points

Nov 15, 2017 12:45 PM in response to amytom12

Looks fine. As a test, insert your DVD, reboot your Mac and hold Alt/Option key. Do you see the DVD icon as a selection in the Boot Manager?

Loner T

Level 9

59,536 points

Nov 16, 2017 5:42 PM in response to amytom12

Can you boot into Internet Recovery and run

diskutil repairDisk disk0

and post the output?

Loner T

Level 9

59,536 points

Oct 16, 2017 11:15 AM in response to amytom12

You do not need to boot into BIOS because Macs do not have a user interface for BIOS or UEFI. The installation method determines the type of installation. The msinfo32 command should provide the current type. It can be changed by re-installing Windows, provided some prerequisites (a MBR and the legacy BIOS boot is used) are setup correctly.

On a 2011 Mac, the default is BIOS, if you use the built-in Optical drive to install Windows.

amytom12 Author

Level 1

12 points

Oct 16, 2017 2:26 PM in response to amytom12

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.

amytom12 Author

Level 1

12 points

Oct 17, 2017 5:15 AM in response to Loner T

Sure I will do that! One question, what type of DVD do I need? Do I need a Windows install disk or just any normal music DVD? I have some left-over music DVD's and could I just erase all the data on there and use it for the installation?

Loner T

Level 9

59,536 points

Oct 17, 2017 8:16 AM in response to amytom12

Yes. You may want to use a DVD-R SL blank disc and get the ISO from Download Windows 8.1 Disc Image (ISO File) and burn it to the blank disc. Ti burn the Iso to blank disc, right-click on the downloaded ISO, choose Burn, expand the dialog box, and choose the Verify and Mount options and the lowest Burn rate supported by your media.

amytom12 Author

Level 1

12 points

Oct 17, 2017 1:48 PM in response to Loner T

Oh, by the way. I did used x code a while back to fix the 2 option issue. Now I have 3 options : Create a Windows 7 or 8 version install disk, Download the latest windows support software from apple, and install windows 7 or 8. Which one do I pick?

Loner T

Level 9

59,536 points

Oct 17, 2017 2:20 PM in response to amytom12

amytom12 wrote:

Hello! I just searched through my DVD pile and found 2 DVD types : DVD + R DL and DVD - R. Will these work? I don't have any DVD-R SL's though.

DVD-R by default is SL (Single Layer), and should have a capacity of about 4.75Gb. It should work.

amytom12 Author

Level 1

12 points

Oct 17, 2017 3:39 PM in response to Loner T

Sure, i'll do that. I just found out my disc is not RW and I have data on it. I tell you the results on the weekend because on Sunday or Sat., I'll be going to out to buy a DVD pack. Thank you for your help! Talk to you on the weekend.

Loner T

Level 9

59,536 points

Nov 12, 2017 11:18 AM in response to amytom12

Your disk looks clean. You may want to disconnect the 32 GB USB drive, and check if the Install check box in BC Assistant is enabled. If it is enabled, check the Install box, and click on Continue and follow prompts.

Loner T

Level 9

59,536 points

Nov 12, 2017 12:33 PM in response to amytom12

You are not in the directory where the ISO is located. Right-click on ISO file in Finder, and select Get Info. Copy the path (without the filename), and in Terminal, type

cd <Paste/Path/Using/Command+V>

and now run the same commands which I gave you earlier.

amytom12 Author

Level 1

12 points

Nov 12, 2017 3:35 PM in response to Loner T

Okay. I was just experimenting with the openssl md5 command in terminal, and I found out that when I type down "openssl md5 (File Path)" it doesn't work for the windows iso file but I did the same thing with another file and it did work. I think the ISO file does not provide you was a checksum.

This is a QuickTime clip I took:

iMac:~ XXXXXXX$ openssl md5 /Users/XXXXXXX/Desktop/Clip\ 1.mov

MD5(/Users/XXXXXXX/Desktop/Clip 1.mov)= b7917d796d8c9788bba51a810af727ff

iMac:~XXXXXXX$

And this is with the ISO file:

iMac:~ XXXXXXX$ openssl md5 /Users/Tom-Tran/Desktop/Win8.1_English_x64.iso

There is no long string of code like the one above. Does this mean that the ISO file is corrupted?

Loner T

Level 9

59,536 points

Nov 12, 2017 3:49 PM in response to amytom12

amytom12 wrote:

And this is with the ISO file:

iMac:~ XXXXXXX$ openssl md5 /Users/XXXXXXX/Desktop/Win8.1_English_x64.iso

There is no long string of code like the one above. Does this mean that the ISO file is corrupted?

Does the command complete successfully? Does the 'ls -lg' command complete on the ISO file?

amytom12 Author

Level 1

12 points

Nov 12, 2017 4:06 PM in response to Loner T

Ok this is what I got when I did " ls -lg (File Path)

iMac:~ XXXXXX$ ls -lg /Users/XXXXXX/Desktop/Win8.1_English_x64.iso

-rw-rw-rw-@ 1 staff
4320526336 Jul 21 19:50 /Users/XXXXXX/Desktop/Win8.1_English_x64.iso

iMac:~ XXXXXX$

So yeah, it does work successfully. Sorry for the inconvenience. 😕

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