Can't erase failed install

[matty.p]

I attempted to install HS on an external SSD which failed at about 80%. I was able to restart and get back to my main internal HD without any problems. I went into disk utility to try and erase the external and try and reinstall. However I can't seem to get disk utility to reinstall or erase the external HD.

I have tried multiple erase options but I always get the same error, "Couldn’t communicate with a helper application."

Any help would be appreciated

 

[justperry]

I attempted to install HS on an external SSD which failed at about 80%. I was able to restart and get back to my main internal HD without any problems. I went into disk utility to try and erase the external and try and reinstall. However I can't seem to get disk utility to reinstall or erase the external HD.

I have tried multiple erase options but I always get the same error, "Couldn’t communicate with a helper application."

Any help would be appreciated

Have you tried to erase the disk from the recovery disk Partition?

Hold CMD-R at startup.

 

[matty.p]

Have you tried to erase the disk from the recovery disk Partition?

Hold CMD-R at startup.

Tried that just now, same error.

 

[grahamperrin]

Try a reset of NVRAM.

… tried multiple erase options but I always get the same error, "Couldn’t communicate with a helper application." …

If that error recurs, please provide a screenshot of Disk Utility; for us to see exactly what is selected.

Also, please let us have output from the following commands:

diskutil list

diskutil APFS list

diskutil coreStorage list

Hint: for legibility, use the ⊞ icon to paste as code.

 

[Stefan johansson]

1, find a windows computer
2, connect to disk
3, format disk
4, problem solved.

 

[justperry]

1, find a windows computer
2, connect to disk
3, format disk
4, problem solved.

HFS+, Guess not.

But joking aside, think I get where you want to go, first Format it with Windows, next try to do it again using DU, format as HFS+ GUID.

Try a reset of NVRAM.



If that error recurs, please provide a screenshot of Disk Utility; for us to see exactly what is selected.

Also, please let us have output from the following commands:

diskutil list

diskutil APFS list

diskutil coreStorage list

Hint: for legibility, use the ⊞ icon to paste as code.

Don't think a PRAM/NVRAM reset will work, neither a SMC reset.
Disk Utility is fairly crappy nowadays, just a few OS versions ago it never failed on me, that's not the case anymore.

 

[grahamperrin]

Don't think a PRAM/NVRAM reset will work, neither a SMC reset.

Not an SMC reset.

NVRAM is a long shot based on the 'stickiness' that was known to occur, in some cases, with interruptions to installation of earlier versions of the OS.