Big Sur, Boot Camp and Windows 10 version 20H2 problems

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Big Sur, Boot Camp and Windows 10 version 20H2 problems

Upgraded my 1TB SSD to a 4TB SSD in my iMac 27-inch 5K (Late 2015). Had lots of difficulty, ended up erasing everything and starting over as recommended by Loner T. Disk Utility output now looks like this:

The steps I took to reinstall MacOS then W10 (then MacOS again!) as well as the diskutil list output from Terminal looks like this:

Terminal "diskutil list" output

Things still aren't working right in W10. For example, several drivers are missing and the Date and Time settings won't stick. I was going to attempt a repair via Boot Camp Assistant and Boot Camp drivers downloaded to a Windows install USB stick, but BCA proceeded as though it was going to create a new BC partition. I chickened out because I do not want to spend another 2 days and 2 nights restoring MacOS and W10 with all the apps and docs.

Is my latest partition|container|volume layout the way Apple intended? What's the best way to update the drivers for Boot Camp?

Thanks in advance for your help or suggestions.

iMac 27″, macOS 11.2

Posted on Apr 6, 2021 11:01 AM

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Answer 1

Best reply

Loner T

Level 9

59,471 points

Apr 6, 2021 1:43 PM in response to Francis Drouillard

A Windows System Restore is 'blind' it has not respect fro any other OS/partition on the disk. It assumes it has full access. Are you familiar with Winclone?

Deleting the 50GB disk0s2 will not help much.

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Answer 2

Apr 6, 2021 1:37 PM in response to Loner T

Thank you for your helpful reply.

The non-standard layout may be the result of restoring a Windows System Image, which erased my MacOS partition. In other words, after restoring my W10 apps and docs, I no longer had a choice to startup in MacOS. I had to reinstall Big Sur.

A default Windows display driver was installed. I downloaded the needed drivers from the AMD website so the display is now OK. Audio still doesn't work. I have to reset the Date and Time every time I restart Windows. Outlook is misbehaving and can't connect to my iCloud eMail account.

I don't see any unknown devices in Device Manager. Other devices include:

FaceTime HD Camera (Built-in)
PCI Memory Controller
SM Bus Controller

All three show a yellow triangle with exclamation point.

Windows update found drivers for all but FaceTime HD Camera (Built-in). I need to restart and see if that fixed anything.

In the end I want to see a standard partition layout. Is it feasible to simply delete the 50 GB APFS volume (disk0s2)?

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Answer 3

Loner T

Level 9

59,471 points

Apr 6, 2021 11:30 AM in response to Francis Drouillard

Your layout is non-standard, since you have a 50GB APFS and a 2TB APFS, and Bootcamp is in the middle of the two.

Installing Drivers, since you already have OSXRESERVED, should be easier, since you have the Bootcamp drivers. Are there specific devices that are not working? Can you look for Unknown and Other devices in Windows Device Manager?

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Answer 4

Apr 6, 2021 2:08 PM in response to Loner T

Thank you for the Winclone recommendation, I'll give it a go.

You've been very helpful with this problem, but I'd like to ask you one more question: Would it be adequate to use BCA to delete the W10 partition, then use Disk Utility to delete the 50 GB APFS volume, then use BCA to reinstall Windows 10? Or should I nuke everything and start over? Again, my goal is to achieve a standard MacOS and Boot Camp partition layout.

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Answer 5

Loner T

Level 9

59,471 points

Apr 6, 2021 4:29 PM in response to Francis Drouillard

I am running Windows on a macOS Catalina 2018 Mini. My Big Sur installation is currently experimental and does not have W10, because of issues between the two OSes.

This is the layout from the 2018 Mini. The 4TB layout should also look similar, since you have 2015 Mac. Both support a UEFI-only installation of Windows.

  #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk2
   1:                        EFI EFI                     314.6 MB   disk2s1
   2:                 Apple_APFS Container disk3         1.6 TB     disk2s2
   3:       Microsoft Basic Data BOOTCAMP                387.8 GB   disk2s3

/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.6 TB     disk3
                                 Physical Store disk2s2
   1:                APFS Volume Macintosh HD            11.2 GB    disk3s1
   2:                APFS Volume Macintosh HD - Data     107.3 GB   disk3s2
   3:                APFS Volume Preboot                 82.5 MB    disk3s3
   4:                APFS Volume Recovery                528.9 MB   disk3s4
   5:                APFS Volume VM                      2.1 GB     disk3s5

The other two are backup disks.

/dev/disk0 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *4.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS TBay-T1                 4.0 TB     disk0s2

/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *4.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:                  Apple_HFS TBay-T2                 4.0 TB     disk1s2

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Answer 6

Loner T

Level 9

59,471 points

Apr 6, 2021 2:19 PM in response to Francis Drouillard

My recommendation is

Backup macOS using the tool of your choice
Erase the whole disk
Restore your macOS backup
Install a new copy of Windows or restore an older backup using Winclone.

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Answer 7

Apr 6, 2021 3:19 PM in response to Loner T

Do you have a BC partition on your Mac running Big Sur. If so, would you mind sharing a screenshot of Disk Utility set to Show All Devices? It would be good to see what a proper layout looks like.

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Big Sur, Boot Camp and Windows 10 version 20H2 problems

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