Hi all, I had issues after removing an old Bootcamp partition, now most of the drive can not be erased, even in Diskutil in Terminal.
I can erase parts of the disk, but even then they won't mount, and certainly can not just erase the whole thing back to a single drive, which is what I am trying to do.
Thank you for any suggestions.
Mac Pro, macOS 10.12
The DriveDX report does have a warning about the "SATA Downshift Error Count" (attribute# 183). At the very least you have some sort of hardware issue going on which is causing the SATA link speed to drop from 6Gb/s to 3Gb/s. I've never seen this attribute listed with a warning on any of the hard drives I've checked. It is possible the hard drive itself is the cause of the problem. I would try using the drive in another bay to see what happens to see if you can determine if the drive bay or the drive itself has the problem. You can check the "RAW Value" for attribute# 183 to see if the value continues to increase as well as checking to see if the drive is connected at 6Gb/s or 3Gb/s. You could also try erasing the drive when it is connected externally, although that may not be as good of a test.
The DriveDX report does have a warning about the "SATA Downshift Error Count" (attribute# 183). At the very least you have some sort of hardware issue going on which is causing the SATA link speed to drop from 6Gb/s to 3Gb/s. I've never seen this attribute listed with a warning on any of the hard drives I've checked. It is possible the hard drive itself is the cause of the problem. I would try using the drive in another bay to see what happens to see if you can determine if the drive bay or the drive itself has the problem. You can check the "RAW Value" for attribute# 183 to see if the value continues to increase as well as checking to see if the drive is connected at 6Gb/s or 3Gb/s. You could also try erasing the drive when it is connected externally, although that may not be as good of a test.
you can usually use Disk Utility to erase the entire device, but you must be able to select the immutable device-name.
you need device-view:
otherwise you just get the data Volumes:
HWTech: GPT-formatted disks have a partition tables at the low address range and a backup at the high address range. You’ll want to dd both ranges to clear, or expect the occasion surprise when things get repaired.
MrHoffman wrote:
HWTech: GPT-formatted disks have a partition tables at the low address range and a backup at the high address range. You’ll want to dd both ranges to clear, or expect the occasion surprise when things get repaired.
It doesn't seem to matter when macOS gets confused. I think as long as there is no hint of any partitioning at the beginning of the drive macOS doesn't even think to check the backup. At least I've never encountered a case where the backup partition table interfered. It is always something to keep in mind though for the extreme cases. Thanks for pointing it out.
HWTech wrote:
MrHoffman wrote:
HWTech: GPT-formatted disks have a partition tables at the low address range and a backup at the high address range. You’ll want to dd both ranges to clear, or expect the occasion surprise when things get repaired.
It doesn't seem to matter when macOS gets confused.
Having worked with a version of EFI that automatically (and silently!) fixed a corrupt GPT, don’t bet on that.
Sorry, should have added that repair disk come up with no errors.
Here is the info on the disk...
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk1
1: EFI EFI 209.7 MB disk1s1
2: Microsoft Basic Data 248.8 GB disk1s2
3: Apple_Boot Blank 650.0 MB disk1s3
4: Microsoft Basic Data 650.0 MB disk1s4
5: Apple_HFS hhhh 250.0 GB disk1s5
6: Microsoft Basic Data 1.5 TB disk1s6
Ignore the weird names (i.e. hhhh etc) I was just trying to format them in Terminal. Weird thing is that first one and last one are NOT formatted for Windows despite what it says. the first I can reformat to Mac OS but won't mount, and the last one was never formatted for windows, it just went weird when I reformatted the first one after getting rid of windows....which I failed to do via Bootcamp, but only because it wouldn't allow me to. At this point I just want to wipe the whole darn thing :)
Hello gain,
I have done as shown, and now see this is Terminal...
/dev/disk1 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *2.0 TB disk1
But I still get it filing when I try to erase the disk. Its says, "cannot open device".
Drive DX dis not have any serious error that I can see, but I can see the option for advanced info you mentioned sorry. But I can save the report. Here is part of it below..
Thank you, but yes I can see that.
Tried to repair and got this...
Good to know. Thanks.
With more recent versions of macOS Disk Utility hides the physical drives from the default view. Within Disk Utility you need to click on "View" and select "Show All Devices" before the physical drives are seen in the left pane of Disk Utility.
Sometimes macOS & Disk Utility just get confused when it encounters an unexpected situation in the partition layout. In that case make sure all volumes are unmounted (but not ejected) and zero out the first part of the drive destroying the current partition layout. You do this using the "dd" command. This command is nicknamed data destroyer so make sure you use the proper disk identifier in the command in place of "diskN" in my example:
Unmount all volumes on "diskN" which you want to erase:
diskutil unmountDisk diskN
Zero out the first 1GB of the drive "diskN" to destroy the partition table (a little overkill):
sudo dd if=/dev/zero of=/dev/diskN bs=10m count=100
Using the information in your post the commands would translate to:
diskutil unmountDisk disk1
sudo dd if=/dev/zero of=/dev/disk1 bs=10m count=100
Note: If you booting into Recovery Mode, then you don't need to use "sudo" on these commands since you are already root. After zeroing out the beginning of the drive and destroying the partition table you should be able to use Disk Utility to erase the drive normally.
This all assumes the hard drive is healthy and not beginning to fail. Unfortunately macOS and the Apple Diagnostics do not do a very good job of assessing drive health. If you are booting from a full install of macOS, then you can check the health of the hard drive by running DriveDX which can identify many more types of early drive failures especially if a user can interpret the SMART attributes. Feel free to post the report here using the "Additional Text" icon which looks like a piece of paper.
So I tried loading into diagnostics mode, but it would not do so....but when I booted back in and tried to format the drive again it now worked fine.
Thanks everyone!! Especially HWTech!! Legend.
Might have to look into my fans though as all my drives are hot according to DriveDX report
Hey mate, by "DiskN', am I replacing "N' with "1"?
Thanks for your help!!!
Nevermind, sorry I obviously did not read the first sentence properly :)
I can see the Physical drive in Disk Utility BW, it is still on Sierra.
Corrupted partition table