Solution to when you are unable to re-install macOS High Sierra
Pressing the Command + R then trying to re-install. Getting the following error.
“This disk doesn’t use the GUID Partition Table scheme… Use Disk Utility to change the partition scheme. Select the device containing the disk, click the erase button, select the Volume Scheme and then click Erase.“
The erase option was not available!
Here is the RESOLUTION:
Step #1 Hold down the Command+R to get into the Recovery Mode.


Step #2 From the macOS, Utilities go to Disk Utility


Step# 3 In the Top Menu go to View – Show All Devices.


Step #4 Now within the Internal option, you will be able to see the Hard Drive (Shows Hard Drive Make and Model).
Select the TOP part of the Hard Drive, and click the Erase button.


Step# 5 Name your Hard Drive, verify the Format is Mac OS Extended (Journaled)
Step #6 Set the Scheme to: GUID Partition Map


Step #7 Try Again.
Props to – ComputerTipsLaiju for the guidance!