Boot Camp Assistant causes unexpected reboot (crash?) on macOS Sierra

Question

Level 1

24 points

Boot Camp Assistant causes unexpected reboot (crash?) on macOS Sierra

Trying to use Boot Camp with macOS Sierra on a late-2013 iMac. Boot Camp Assistant seemed to properly modify the USB drive as well as repartition the HDD.

Subsequently, it asked for the password to unlock system preferences. Immediately after the password had been entered, the system rebooted without further notice. It did not boot from the USB drive, nor did Boot Camp Assistant resume after logging in. Therefore I believe this was an unexpected reboot (a crash?). Notably, the iMac had lost network connection after the reboot! After another (manual) boot, the system appeared to be back to normal operation.

Has anyone experienced this behaviour? Is this a known bug in macOS Sierra?

Any chance to cleanly complete the process?

Best regards

iMac (27-inch, Late 2013), macOS Sierra (10.12)

Posted on Oct 22, 2016 1:05 PM

Reply

Answer 1

Loner T

Level 9

59,536 points

Oct 22, 2016 9:39 PM in response to ohw0205

What other external devices and/or storage did you have connected to your iMac during this installation?

Reply

Answer 2

ohw0205 Author

Level 1

24 points

Oct 22, 2016 11:30 PM in response to Loner T

External devices connected:

- Time Machine backup HDD (switched off)

- USB wireless kb/mouse (switched off, using Apple kb/mouse instead)

Maybe unrelated to this problem, I found that my wireless USB 3-button mouse would intermittently freeze as soon as a USB stick was connected. Since this never occurred in ElCapitan, I suspect it's another newly-introduced bug in Sierra...

Reply

Answer 3

ohw0205 Author

Level 1

24 points

Oct 23, 2016 1:53 AM in response to ohw0205

Just gave it another try:

- physically disconnected all external devices

- removed Windows partition

- re-initiated partitioning and Windows installation (3rd item in Boot Camp Assistant task list)

=> Same result: reboot as startup disk preferences are being modified; machine comes up without network ⚠; back to normal after another reboot

=> No (obvious) way to get Windows installed. Annoying ...

Reply

Answer 4

Loner T

Level 9

59,536 points

Oct 23, 2016 6:52 AM in response to ohw0205

ohw0205 wrote:

Just gave it another try:

- physically disconnected all external devices

- removed Windows partition

- re-initiated partitioning and Windows installation (3rd item in Boot Camp Assistant task list)

=> Same result: reboot as startup disk preferences are being modified; machine comes up without network ⚠; back to normal after another reboot

Does the Windows Installer start? If not, is the NTFS-formatted partition still on the Mac? If yes, reset SMC/NVRAM, connect USB Installer, reboot Mac and hold Alt/Option key and if you have Windows and EFI Boot from the USB, try Windows first (this is the legacy BIOS installer). Try EFI Boot if it fails, which may also fail with a GPT vs MBR error, which can be corrected.

Reply

Answer 5

ohw0205 Author

Level 1

24 points

Oct 27, 2016 9:09 AM in response to Loner T

The Windows installer did not start, the system rebooted into macOS instead. Yes, the BOOTCAMP partition was present (btw, it was not formatted as NTFS, as others have noted before; has Boot Camp ever created correctly formatted NTFS partitions?).

Indeed, installation of Windows was possible by choosing the installer at boot time; I selected the EFI boot version since that seemed the natural choice on an EFI-based system. Couldn't find any documentation on which choice Boot Camp Assistant was supposed to make, though.

The question remains why BCA failed to boot into the installer; either the boot drive was not chosen correctly or the system did not accept the flash drive (quickly enough) at boot time...

One more thing is still unresolved:

In the boot manager invoked with the option key, my Apple BT keyboard works, but the mouse does not! The same is true within Windows (ended up installing with keyboard only). In the installed system both devices are shown as paired.

A third-party wireless USB keyboard and mouse work perfectly both in the boot manager and within Windows.

Needless to say, the Apple keyboard and mouse function normally in macOS.

Any ideas?

Reply

Answer 6

Loner T

Level 9

59,536 points

Oct 27, 2016 9:45 AM in response to ohw0205

ohw0205 wrote:

The Windows installer did not start, the system rebooted into macOS instead. Yes, the BOOTCAMP partition was present (btw, it was not formatted as NTFS, as others have noted before; has Boot Camp ever created correctly formatted NTFS partitions?).

OSX/BCA cannot create a NTFS partition. It creates a FAT32 partition, which must be formatted by user in the Windows installer.

Indeed, installation of Windows was possible by choosing the installer at boot time; I selected the EFI boot version since that seemed the natural choice on an EFI-based system. Couldn't find any documentation on which choice Boot Camp Assistant was supposed to make, though.

The question remains why BCA failed to boot into the installer; either the boot drive was not chosen correctly or the system did not accept the flash drive (quickly enough) at boot time...

EFI vs BIOS is derived based on Mac Model Identifier, and Windows version. BCA will set appropriate NVRAM variables to start the correct installer. Usually a SMC/NVRAM reset will correct this issue.

One more thing is still unresolved:

In the boot manager invoked with the option key, my Apple BT keyboard works, but the mouse does not! The same is true within Windows (ended up installing with keyboard only). In the installed system both devices are shown as paired.

A third-party wireless USB keyboard and mouse work perfectly both in the boot manager and within Windows.

Needless to say, the Apple keyboard and mouse function normally in macOS.

Any ideas?

This is related to BT Link Keys on devices. Windows does not handle already paired devices for pairing well. Unpair the devices from all pairings, pair to Windows first, and then pair with OSX second.

Reply

Answer 7

ohw0205 Author

Level 1

24 points

Oct 27, 2016 9:47 AM in response to Loner T

Good to know, thank you! But shouldn't the BT mouse work in the boot selector, which is an Apple piece of code?

Or is a BT mouse just not supported by design at this point?

Reply

Answer 8

Loner T

Level 9

59,536 points

Oct 27, 2016 9:53 AM in response to ohw0205

A BT mouse should work during Windows installation. The design is supposed to seamlessly carry over the pairing between the two OSes and the installer. I have very rarely seen it work as designed. The $WinPEDriver$ directory contains the Apple drivers which support the Windows Installer.

Reply