How do I reformat my 2019 iMac Pro Retina i9 hard drive? I have it booted off of a remote drive and have migrated my data. Disk Utility is returning a (-69845) Space manager invalid error. I have read that trying from a terminal prompt might work. Any info would be appreciated. The drive is a 1TB SSD PCI-Express.
iMac (2017 – 2020)
thepopp wrote:
Thanks for the reply D.I.
I failed to mention that those tasks were both tried, a few times, and were unsuccessful. The 'Erase' process runs and says it was successful, but when I try to install a new OS (Sequoia) it says it cannot because of an unexpected file structure. I read a thread online that suggested that a terminal approach might work...
You need to erase the whole physical drive as GUID partition and APFS (top option). Within Disk Utility you need to click "View" and select "Show All Devices" before the physical drive appears on the left pane of Disk Utility.
If your iMac has a Fusion Drive (a Hard Drive combined with an SSD), then you will want to erase the Fusion Drive portion/item as GUID partition and APFS (top option).
If the Fusion Drive was broken by any of these erase attempts, then you can use the following Apple article to recreate the Fusion Drive prior to installing macOS.....just make sure the Fusion Drive is using the APFS file system.
FOLLOW UP: I was finally able to reformat the drive. I formatted it using the old FAT format and then reformatted back into APFS. This seems to have worked for now.
I don't know the ins and outs of Terminal for your case here, but you may be able to correct the directory error by launching Disk Utility and running First Aid on the internal drive.
• Launch Disk Utility and click View > Show All Devices.
• Then select the drive device at the top of the list and run First Aid on that. Also run First Aid on any container and every volume on that drive. You might run a couple passes on each.
When done, try again to erase the drive and reformat it.
How to repair a Mac storage device with Disk Utility - Apple Support
Erase and reformat a storage device in Disk Utility on Mac - Apple Support
You might find this older Community thread of interest: How to fix File system verify or repair f… - Apple Community
Thanks for the reply D.I.
I failed to mention that those tasks were both tried, a few times, and were unsuccessful. The 'Erase' process runs and says it was successful, but when I try to install a new OS (Sequoia) it says it cannot because of an unexpected file structure. I read a thread online that suggested that a terminal approach might work...
Thanks HWT. I tried so many things that I may have done this before I saw your reply. I did post an update however that I was finally able to reformat into the old FAT file structure, and then reformat again back into the APFS format. Not sure which fixed, but it appears to be working now.
Reformatting a 2019 iMac, i9 Intel hard drive from terminal.
