Error: -69760: Unable to write to the last block of the device".

Oops! Forgot one.

1. Restart the computer. Immediately after the chime hold down the Command-R keys until Apple logo and progress bar appear.
2. Wait until the Utility Menu appears. Select Disk Utility then click on the Continue button.
3. After Disk Utility loads select the drive (out-dented entry with type and size info) from the side list. 
4. Click on the Erase button in the Disk Utility toolbar. A panel should drop down.
5. In the drop down panel set the partition scheme to GUID. Set the Format type to APFS (SSDs only) or Mac OS Extended (Journaled.)
6. Click on the Apply button and click on the Done button when it is activated.
7. Quit Disk Utility.

One possible solution:

I just had the same problem with an external USB disk that I tried to repartition. No matter what I did (using diskutil and dd in the Terminal, ...) I couldn't get rid of the error.

But then I plugged it into a Linux box and partitioned it there without any problems.

When I plugged the disk back into the Mac, I could format the linux-created partition with Journaled HFS+. Problem solved!

Another possible solution:

I managed to create a single partition on the entire disk by running this command:

diskutil eraseVolume jhfs+ "Volume Name" /dev/disk# [substitute # with your disk number.]

To get the disk number you need to run "diskutil list" and identify this disk's number from the listing.

Last possible solution:

Format the disk using all 0's. This is a Security Erase. It takes a lot of time. Not the best thing to do to an SSD but may be required.