Catalina Install Failure on Fusion Drive w/ BOOTCAMP Partition

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Catalina Install Failure on Fusion Drive w/ BOOTCAMP Partition

I tried to upgrade my late 2015 27" Retina iMac from Mojave to Catalina. The internal drive is a 3TB Fusion drive w/ a 200 MB BOOTCAMP partition. When the system rebooted after the upgrade it goes to a screen that says (something like) "You Mac was restarted due to an error." After a couple of minutes it reboots and the same screen comes up.

I tried using Recovery Mode to erase the Macintosh HD partition and reinstall. This gave me the same result. I tried unplugging for 15 seconds, and booting with CMD+OPT+P+R. No difference. I also tried booting in Internet Recovery mode, erasing and reinstalling. Still doesn't work.

FWIW the BOOTCAMP partition boots and Windows comes up w/o any problems.

I have a copy of the Catalina Public Beta on an external SSD, and that boots and runs fine.

I guess I could try removing the BOOTCAMP partition, but there's no bootable MacOs on that drive, so no way to run BOOTCAMP Assistant. Can I delete the BOOTCAMP volume and repartition using Disk Utility in Recovery Mode?

Any other suggestions?

iMac Line (2012 and Later)

Posted on Oct 8, 2019 5:17 PM

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Answer 1

Best reply

Verne Arase

Level 1

80 points

Oct 16, 2019 8:18 PM in response to emader.casa.bonita

I had a similar problem - 3 TB fusion drive with 200 GB Boot Camp and a Catalina install on the Mac side which ended in errors.

I'd been experiencing hangs of 10 min - hours (which would always recover with no log entries) under Mojave. I'd repeatedly erased the APFS disk and reinstall Mojave and migrate data back using Migration Assistant, but the hangs persisted.

Anyway, once I had some time after Catalina went golden I tried installing Catalina on a freshly erased APFS partition, but it would keep failing midway through. Eventually I got desperate enough to delete the Boot Camp partition, and was left with a strange situation that the GUI Disk Utility would see as a 2.8 TB APFS partition with 2.x TB free. I eventually somehow got rid of the APFS partition, and ended up with a 5.x TB fusion drive sitting on a 3 TB rotating drive fused to a 128 GB SSD.

I couldn't figure out how to break apart the fusion drive using my usual tricks because 'diskutil cs list' showed no core storage volumes. I couldn't figure out how to reformat the disk (and I didn't want to pry apart my iMac), so I built a bootable flash Catalina installer drive and eventually found the 'diskutil resetFusion' command which did rebuild the fusion drive with a fresh APFS file system on it.

This probably destroys all data on the drive, so only use it as a last resort.

BTW, once I'd done that, I could install a fresh Catalina on it and used migration assistant to migrate all my stuff back from a Mojave clone to the Catalina system. This system remains stable without those hangs, so I credit my munged partition table with all those hangs.

I've yet to reinstall Boot Camp as it's been so long since I've had a stable system, that I'm reluctant to mess with it. Maybe when the new Win 10 shows itself to be stable, or I get sufficiently hungry to game again. Since I'm retired now, I don't need it for work.

Anyway, good luck!

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Answer 2

Oct 10, 2019 7:30 PM in response to emader.casa.bonita

I booted into Recovery Mode and restored from my Time Machine backup. This got me back to where I was before starting the Catalina install. I installed WinClone, used it to backup my Boot Camp volume and then used Boot Camp Assistant to remove the Boot Camp Volume. The assistant seemed to remove the volume, and then complained that there was another volume on the disk. Disk Utility showed a small ~300 GB partition.

I’m now trying the Catalina install again. Hope it wasn’t the extra partition that was the problem last time. If it was, I may have to repartition the internal drive and restore from the Time Machine backup after the install...

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Answer 3

Oct 19, 2019 1:54 PM in response to Verne Arase

The internal drive had free space the same size as the Boot Camp partition. I tried to partition the drive to get rid of it, and I got an error saying the fsroot tree was invalid. I tried to repair the drive and it just complained about the fsroot tree and failed.

I booted into Internet Recovery Mode, opened the terminal, did "diskutil resetFusion" and then installed Catalina. The install worked and I was able to restore from my Time Machine backup! Still haven't tried to recreate the Boot Camp partition.

Thanks for the tip!

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Answer 4

Big Iron

Level 1

18 points

Oct 19, 2019 6:05 PM in response to emader.casa.bonita

Glad it worked.

This seems to point to a bug in old versions of diskutil, Boot Camp, or the APFS conversion, not sure which.

I don't remember resetFusion being in there before, but I may have missed it. If it's a recent addition, it may be Apple's tacit admission that they created a problem - but it's useful in any case and certainly easier than deleting a physical disk out of the logical fusion drive, then rebuilding it.

Now ... who's going to bell the cat and try to create a Boot Camp :-).

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Answer 5

Oct 10, 2019 8:05 PM in response to emader.casa.bonita

Sigh... the install still fails. Guess I have to repartition the internal drive. :-(

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Catalina Install Failure on Fusion Drive w/ BOOTCAMP Partition

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