Boot Camp on 2020 iMac 5K

Interesting ... well, I tried it again.

Again BCA initiated the installation and Win 10 2004 installed just fine (except this time the Boot Camp install didn't complete). I may have prematurely terminated it by rebooting after tons of dialogs leapt out at me telling me I'd have to reboot to proceed.

So, after installing Win maintenance seeing there was no Boot Camp I read an article about using BCA to grab the Boot Camp Win installer and rebooted into macOS.

Ran BCA and - surprise - BCA would allow me to remove the Boot Camp partition. Instead I downloaded the boot camp software on a flash drive and rebooted into Windows.

Installed the boot camp software, 1password, logi options, steam, and a AMD Mac driver package (good for all iMacs since some iMac lost in history) and rebooted into macOS. Everything seemed fine so I upgraded Parallels to 16, installed it, and went into Parallels to install on Boot Camp and - no Boot Camp option.

Odd I thought, so I went into Disk Utility and it hung during initialization. Tried to restart macOS and it hung on shutdown. Rebooted and tried to shut down again and again it hung.

Rebooted into recovery mode and run First Aid against Main and Main - Data and all checked out fine. Then for yucks went into the Startup Utility and set the Mac to boot off of anything.

Rebooted back into macOS and now Parallels sees the boot camp disk. Restarted and it restarted fine.

Everything seems copasetic except Parallels runs like a dog and won't let me set a resolution higher than something like 1200p, and it runs dog slow even given 10 cores and 64 GB. It wants to use system memory for graphics despite the fact that the Radeon Pro 5700 XT has 16 GB. I'd started out in "game" mode, so I reset it to productivity mode and gave it four cores and 32 GB - performance seemed identical.

Methinks I'm a tad too far ahead of the curve now - not sure Apple's recognizing Win 10 2004 as a trusted boot source, and Parallels doesn't seem too optimized at all for this Mac. At least everything's working though and the Mac will restart cleanly.

So ... I guess I'll just hobble along and wait for everything to catch up. Maybe if I'm bored I'll boot into Windows and try to install a game.

... or maybe I'll reengage with Netgear and Bitdefender over my RBK853s over Netgear Armor and the Orbi Wifi 6 routers. So many support calls, so little time ...

-- Thanks, Verne

Did you install boot camp drivers from a flash drive formatted by BCA?

It's all relative paths ... I copied all the files from the flash drive and pasted them into a folder in my Downloads folder and ran it from there without problems.

Bluetooth works fine ... and this Mac even has Bluetooth 5 - so you'd think the drivers have to be at least somewhat up to date.

I just went through a thing where I'd installed inappropriate drivers which were pointed to by an Apple knowledge base article - I should've known it was talking about older iMacs since it referenced iMacs 2014 - current. I should've know that current is not current (now). Wish those articles would be a bit more explicit, like 2014 - 2019.

I uninstalled those drivers and did a repair on the stuff that the Boot Camp Win software originally restored and things are looking a bit better.

Note to self: don't go out looking for trouble. Only install when something says it needs to be updated.

How'd you format your SSD anyway? GPT partition structure?

Loner T wrote:

BC Assistant is problematic as macOS has marched on from Sierra to Catalina. It has become buggier in every release. APFS is not the best FS implementation, either. The combination has been very problematic.

Tell me about it ... and it's worse on Fusion Drives.

There was an evolutionary inflection point where Fusion Drives - at least the 3 TB variant - couldn't be upgraded between OS releases without reformatting them.

If I never have to do a sudo diskutil resetfusion again I think I could die a happy man.

here are other methods of removing Windows, if BCA fails, without a nuke-and-pave.

I'd be curious to know them, since I'd like to try Boot Camp again but am wary about doing it due to the long recovery time.

Oh yeah.

I bought a 4 TB SSD because my old primary was a 3 TB fusion drive - and of that I've since moved my media off to a Thunderbolt 3 attached RAID array, so I allocated a 500 GB Boot Camp. Also, I've heard that 4 TB and 8 TB drives are installed on a daughter card which would mean that future storage problems wouldn't be soldered on to the mother board.

Can you format a GPT partitioned external SSD and simply put whatever BCA installs on an internal Boot Camp on that drive and Option Boot in to it? (Does BCA put on a NTFS partition or a FAT partition?)

I've never tried to put a Boot Camp on an external drive - I had enough problems trying (unsuccessfully) to put a stable boot camp on a 3 TB APFS fusion drive which is allegedly a supported configuration.

Duhh ... Parallels 16 is running fine now.

Apparently I had to run Parallels tools install myself - I could swear that that happened automagically ... or maybe I'm thinking of VMWare Fusion?

Loner T wrote:

• On APFS, it is bit cleaner

If BCA leaves Free Space, you can use diskutil apfs resizeContainer diskN 0g• , where N is 1 for single-disk Macs and 2 for Fusion Macs.

If BCA leaves partitions, using diskutil eraseVolume, mergePartitions and apfs resizeContainer• verbs are normally used. BCA-assisted remove/restore is retried so it can cleanup the EFI partition.

• On CoreStorage

3TB Fusion requires a Time Machine backup/restore, if the Windows partition is using the 'sandwich' layout. This is the case when Windows partition is less than 1TB, otherwise the resizeVolume• verbs can be used.

I take that my 2020 iMac on Catalina would fall into the first category?

What it looks like happened is that BCA shrank the APFS container and partition by 506 GB and created a 506 GB physical partition. Then it (or Windows) formatted as an NTFS partition.

So I take it that eraseVolume deletes the data in the boot camp physical partition, and mergePartition merges the partition contain the APFS container with the newly formatted (say HFS+) partition, and resizeContainer expands the APFS container to include the newfound space?

How does diskutil know that the filesystem created by eraseVolume contains no data - or can eraseVolume simply delete the filesystem within the physical partition without creating a new filesystem?

This is all so confusing ... is there a logic manual - virtual or dead tree - which describes all this?

I remember a day - waaayyy before I retired - when IBM would distribute their MFT, MVT, SVS, MVS, OS/390, OS Utilities, DFP, etc. programming, program logic, reference manuals on dead tree and virtually on CD. A real snooze to read but quite useful when you needed basic concepts and utilities statement syntax - with example utility statements and what they did. What concept!

Then came Solaris, Windows, and the Mac.

Is there a reference section built in to the developer site at Apple?

-- Thanks, Verne