Bootcamp Windows install issue

Mac Mini 2018 and the OS is Catalina 10.15.6

More info from this morning: I'm able to do a hard shut down by way of the power button on the mini and I can then reboot and I'm able to get to the system startup disk on restart. I'm given the option of booting into Windows via the bootcamp partition that I created but then I get a blue Windows 10 icon and then the Mac Mini becomes unresponisve again. I've tried this a few times and then I gave up and rebooted back into OS X. In the sys prefs under startup disk I'm not given the option to reboot into the Windows bootcamp partition. It's simply not there. Installing Windows via bootcamp has never been easy or straightforward but I've always been able to get it installed in the past and we're talking on everything from old G5 towers to MBP's and even the Mac Mini I'm trying to install on but it's never been impossible. Not sure what's changed.

I've tried re-partitioning maybe 5-6 times so I can't believe it would be an APFS corruption. Checking the partition in disk utility shows it's an NTFS volume. I wish there was an easy way to create bootable media to do the install like in earlier version of bootcamp.

Intel GPU drivers could be it but not sure what the work-a-round would be.

The BC drivers package is 7139. The Windows ISO is the latest available from Microsoft's site.

When I start up BC assistant I see messages saying it's deleting Time Machine backups and then it says it's making room in iCloud for the installation. I don't remember seeing either of these messages wen I've installed Windows successfully.

Glad you got the same messages. I reset the SMC and NVRAM/PRAM and tried the installation again. The Mini goes through the following steps in BC assistant:

Downloads Windows support files

Partitions disk

Copy’s Windows files/ saves 7139

I enter credentials to make system changes

Mac reboots with chime

Screen goes black

Mac becomes unresponsive 

I’m not seeing the blue Windows logo on reboot. Weirdly, I’m not able to turn my monitor off unless I pull the hdmi cable. When I plug the hdmi back in my monitor says it’s not receiving a signal. The power light on the mini is on.

btw, thank you for the help on this. I’m stumped.

The Monitor is an NEC EA275UHD. I've tried a few different HDMI cables and a DVI to Apple Lightning adapter cable that I then use a USB adapter on. Not ideal. I'm going to pick up a USBC to Display Port today and see if that makes a difference.

Couple other things: no other external disks or devices are connected with the exception of the monitor which is connected via HDMI cable.

USB C to display port cable resolved my issue. For some reason the windows installer didn’t like the HDMI cable. With the display port cable Windows installed without any issues.

Thank you LT