can't boot on iMac Pro

Pangalactic

macrumors 6502
Original poster
Nov 28, 2016
368
605
So long story short: I was installing Bootcamp windows, and got an error at the very end. So I went into disk utilities to try to get rid of the windows partition (I couldn't do it through Bootcamp anymore). That didn't work either (it didn't allow me to change the partition size), so I restarted the iMac and erased the main drive in order to reinstall the MacOS.


Now, the iMac Pro is stuck with an endless windows boot cycle: it loads up windows installation, gives me the "a media driver your computer needs is missing" error, and that's as far as I can get.


As far as other options:

1) Interned recovery doesn't work. I can connect to WiFi and get the spinning globe, but there is no progress bar and nothing at all is happening (tested for 8 hours at night)

2) bootable MacOS USB - this is the weirdest thing: the iMac sees them and shows them in the boot menu, but if I chose to boot from them it still goes straight into internet recovery

3) Resetting PRAM and SMC - tried several times, didn't notice any effects.

4) third party "rescue" USBs - the same thing, they are available in the boot menu but iMac goes into internet recovery, which doesn't work.

5) Regular recovery mode also doesn't work and goes into internet recovery immediately


Anything else I can try?


Thank you
 

Pangalactic

macrumors 6502
Original poster
Nov 28, 2016
368
605
Update: still no progress, no matter how I try to boot it for some reason always goes straight into internet recovery mode
 

Superspeed500

macrumors regular
Jul 25, 2013
188
42
So long story short: I was installing Bootcamp windows, and got an error at the very end. So I went into disk utilities to try to get rid of the windows partition (I couldn't do it through Bootcamp anymore). That didn't work either (it didn't allow me to change the partition size), so I restarted the iMac and erased the main drive in order to reinstall the MacOS.


Now, the iMac Pro is stuck with an endless windows boot cycle: it loads up windows installation, gives me the "a media driver your computer needs is missing" error, and that's as far as I can get.


As far as other options:

1) Interned recovery doesn't work. I can connect to WiFi and get the spinning globe, but there is no progress bar and nothing at all is happening (tested for 8 hours at night)

2) bootable MacOS USB - this is the weirdest thing: the iMac sees them and shows them in the boot menu, but if I chose to boot from them it still goes straight into internet recovery

3) Resetting PRAM and SMC - tried several times, didn't notice any effects.

4) third party "rescue" USBs - the same thing, they are available in the boot menu but iMac goes into internet recovery, which doesn't work.

5) Regular recovery mode also doesn't work and goes into internet recovery immediately


Anything else I can try?


Thank you
What happens if you run Apple Diagnostics?
 

Pangalactic

macrumors 6502
Original poster
Nov 28, 2016
368
605
What happens if you run Apple Diagnostics?
I get the spinning globe with "starting internet recovery, this may take a while". With no progress bar, so I'm assuming nothing is happening. I've got 200 Mbps internet here and all downloads go real fast, so whatever the iMac downloads should theoretically take no more than several minutes.
 

Pangalactic

macrumors 6502
Original poster
Nov 28, 2016
368
605
The iMac Pro has a T2 chip. Did you modify Secure Boot to allow booting from an external drive? If not, then that could explain the problem of booting from other drives.
https://support.apple.com/en-gb/HT208330
hmm, this seems to make sense, especially that it always tries to connect to the internet no matter where I boot from.

However, I can't change the Secure Boot settings as CMD + R moves me straight into internet recovery :( are there any other ways to change the secure boot options?
 

CoastalOR

macrumors 68020
Jan 19, 2015
2,458
899
Oregon, USA
hmm, this seems to make sense, especially that it always tries to connect to the internet no matter where I boot from.

However, I can't change the Secure Boot settings as CMD + R moves me straight into internet recovery :( are there any other ways to change the secure boot options?
I'm sorry, but the only way I know of to run the Security app is from Recovery (cmd+r).
 

Pangalactic

macrumors 6502
Original poster
Nov 28, 2016
368
605
Update: I've called the Apple support, and they've suggested plugging in the ethernet cable directly into the iMP. Didn't work. Afterwards, they seemed to be as clueless as I was.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,189
5,538
OP:

Looks like you're going to have to boot to internet recovery and literally "start over".
Hope you made a backup!

BTW, unless you absolutely, positively must have "native Windows bootability", I'd avoid BootCamp.
For running Windows stuff, use an "emulation solution" instead, such as Parallels, VMWare Fusion, or the free "Virtual Box".
Or... if the apps can run with it... you might even try "CrossOver".
 

hobowankenobi

macrumors 6502a
Aug 27, 2015
980
262
on the land line mr. smith.
If you did not change the security settings before starting the bootcamp process...may explain the issue.

All new Macs will have this, you are just on the bleeding edge. Which can be fun, but sometimes painful.

Once you are back to booting, the first thing you should do is decide if you need the new, enhanced security, or if you want to be able to boot to externals, bootcamp, etc. I expect most folks will not want the added security, but will only find out the hard way (when they need to boot to a different source) that they cannot.

It will be a painful learning curve.
 

Fishrrman

macrumors P6
Feb 20, 2009
17,189
5,538
hobo observed:
"I expect most folks will not want the added security, but will only find out the hard way (when they need to boot to a different source) that they cannot.
It will be a painful learning curve."


Perhaps Apple ought to include "an extra step" in the setup assistant process that deals with configuring the t2 chip to the user's needs, or at least advises the new user that configuring the t2 may be necessary in certain situations...
 

hobowankenobi

macrumors 6502a
Aug 27, 2015
980
262
on the land line mr. smith.
hobo observed:
"I expect most folks will not want the added security, but will only find out the hard way (when they need to boot to a different source) that they cannot.
It will be a painful learning curve."


Perhaps Apple ought to include "an extra step" in the setup assistant process that deals with configuring the t2 chip to the user's needs, or at least advises the new user that configuring the t2 may be necessary in certain situations...

Maybe. It would be nice, but I don't expect it of them. Many would turn it off, and not understand the pros and cons.

Same happened a few years back with SIP. We can turn it off, but it goes unmentioned and unknown by the vast majority of users.