<< Solved >> Stuck on "Windows could not prepare the computer to boot into the next phase" error

Update:

I saved my BIOS settings and switched to the BIOS-generated default "optimized" settings.

I also copied the "efi" folder from the USB's WIN11 partition to its EFI partition.

Selecting USB P1 (the EFI partition) gets me a blue screen saying something about being unbootable and recovery.
Selecting USB P2 (The WIN11 partition) gets me a booted USB and a Windows installer.

Proceeded with diskpart approach to preparing the SSD for install, and got stuck at Finishing Up once again.

I'm unable to boot macOS with the BIOS-generated defaults, so I restored my BIOS profile. I need CSM Support Disabled, and Above 4G Decoding Enabled, at minimum. I also have Software Guard Extensions (SGX) Disabled, LEDs in System Power On State Disabled, Legacy USB Support Disabled, and Internal Graphics Disabled in my saved OC BIOS profile - the intent being to give macOS plenty of RAM.

The Windows USB seems happy to boot with either the BIOS defaults or the OC config I'm using.

OK, I tried formatting the SSD as MBR using Disk Utility and that got me to a new error point, though no further and arguably less far than before.

The message this time was "Windows installation encountered an unexpected error. Verify that the installation sources are accessible, and restart the installation. Error code 0xC0000005"

I tried with CSM Support enabled and disabled. No luck either way. One way I get the above, the other I get the same error I've gotten previously.

I've also now tried moving the USB stick to one of the back USB ports since the front ports are USB2 only and the back are USB2/USB3. I'm pretty sure the stick itself is USB2, and in any event moving it to one of my back USB ports made no difference to the outcome.

schlosrat said:

OK, I tried formatting the SSD as MBR using Disk Utility and that got me to a new error point, though no further and arguably less far than before.

The message this time was "Windows installation encountered an unexpected error. Verify that the installation sources are accessible, and restart the installation. Error code 0xC0000005"

I tried with CSM Support enabled and disabled. No luck either way. One way I get the above, the other I get the same error I've gotten previously.

I've also now tried moving the USB stick to one of the back USB ports since the front ports are USB2 only and the back are USB2/USB3. I'm pretty sure the stick itself is USB2, and in any event moving it to one of my back USB ports made no difference to the outcome.

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If your hardware is as per your profile then this is a very strange situation. It should be a doddle to install Windows on it, if only the destination drive is visible to the installer.

Only other thing I can recommend it to use Rufus to make your bootable install USB, because I'm not familiar with the method you've used. It most definitely works.

But as you've said, I'm only making things worse, so ignore me.

schlosrat said:

When I look at the USB in macOS I found that the USB is GUID Partition Map, and it has an EFI partition (disk5s1) that was empty, and then there is a WIN11 FAT32 partition (disk5s2).

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schlosrat said:

Should I remake my USB in some other way so that it has only one partition?

Click to expand...

You might want to format it as MBR with one partition. The EFI partition might be confusing the Windows installer.

UtterDisbelief said:

If your hardware is as per your profile then this is a very strange situation. It should be a doddle to install Windows on it, if only the destination drive is visible to the installer.

Only other thing I can recommend it to use Rufus to make your bootable install USB, because I'm not familiar with the method you've used. It most definitely works.

But as you've said, I'm only making things worse, so ignore me.

Click to expand...

I don't think you're making things worse, and I do appreciate your help. I'll happily try anything I'm able to, and as I hadn't tried your suggestion yet I jumped on it. Each step forward is another clue.

Right now I'm thinking the most common denominator is the USB. I'd use rufus if I could, but I don't have a Windows machine to run it on. Instead, I'm going back to the drawing board to research how to make a good Windows 11 install media. I've got nothing to loose by remaking that and trying again.

Thanks!

jpz4085 said:

You might want to format it as MBR with one partition. The EFI partition might be confusing the Windows installer.

Click to expand...

Worth a shot! I'll try that next. Thanks!

Also, I found this guide that says to use MBR/MS-DOS (FAT) for the USB format, confirming your suggestion.

This is essentially what I did when making my previous USB, except that the guide I was following on that one had me split the install.wim at 3500 I believe, and apparently had me format the USB GUID Part/FAT 32. Otherwise, it was the same process of using Homebrew to get wimlib and using wimlib to split install.wim so that it'll fit on a FAT32 disk.

I've formatted my USB MBR/FAT and I'm copying the files over to it now...

Well, nuts... That didn't work. I hit the same error in the same place.

On the plus side, the MBR USB shows up with just one partition, and reliably boots to the Windows installer. I tried it in both a front USB port and a rear port. Booted from either.

I tried it with my normal BIOS config, and with the BIOS defaults. Got the same results each way.

My procedure has been to use diskpart to nuke all partitions from Disk 0 except P1, which is a 300MB partition. I then use diskpart to re-format P1 FAT32 labeled EFI, just to be on the safe side that any lingering files are removed.

I've tried both creating a primary partition, formatting that NTFS, then deleting it from the Windows installer, and also just leaving the rest of Disk 0 unallocated to select that in the Windows installer. I get the same results either way, naturally.

One option I've not tried yet, and really am not excited about, is to partition the NVMe drive to carve out some space for a Windows install on that. I could then remove the SSD from the system and risk my fully functional Monterey disk by aiming the Windows installer at a partition on it.

If I did something like that, and assuming it worked, would I be able to clone that partition to the 240GB SSD and boot Windows from the SSD that way? And if I did successfully clone a working Windows partition from the NVMe to the SSD, could I then recover the partition space on the NVMe to make it just one partition again without losing my Monterey install in the process?

This sounds like a dubious and desperate plan. I think I'd rather just pull the NVMe back out again and target the SSD, but I've done that once already without success.

Use any VM and use windows through macOS, like Parallels desktop or vmware fusion.

There, create a new USB trough RUFUS.

guindillas said:

Use any VM and use windows through macOS, like Parallels desktop or vmware fusion.

There, create a new USB trough RUFUS.

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Clever idea! Thanks! I've just installed VirtualBox and am downloading the Windows 11 Enterprise VM for it from MS now. I looked at parallels and vmware fusion, but both are paid - and while they do offer a trial period I think I'd be ahead to go with VirtualBox and the free trial of Windows 11. That will give me a longer trial window that can be freely reviewed if I'm not mistaken.

Is there any reason a VirtualBox approach shouldn't work? I did download and install the Oracle VM VirtualBox Extension Pack so I'd have access to NVMe, etc. should I need that.

I suppose I'll know soon enough. Once I've got the VM downloaded and running I'll take a shot at installing Rufus to get that going.

UPDATE: Do NOT Try this with VirtualBox 7.0.2 (the current version at this time). I've painfully managed to confirm what others before have determined. VB 7.0 is not working yet with USB (you can't attach 'em). I've rolled back to VirtualBox 6.1.40, which is supposed to be OK with USB, but so far I'm not having much luck getting the Windows VM to load and run...

Why not create a new usb, through parallels desktop or vm ware, and then use RUFUS.

Also try another USB