Today I received one of the escalated task from my junior to extend existing virtual hard disk on one of the VMware VM using vSphere client, I explored VM settings by right clicking, but found virtual HDD settings are grayed out and it is disabled. At first it looks like Virtual Machine Hardware Version is 11 and options cannot be edited through vSphere client they are restricted but hard disk size can be increased, reference article for the same. So I tried with vSphere web client,
After logging into vSphere web client and below is the screenshot. I was still not able edit and complete options were grayed out. I tried adding another new Hard Disk, extending and deleting it everything was successful. But not on the existing one, I shutdown virtual machine completely but still hard disk was grayed out no luck.
After finding snapshot under snapshot manager (right click VM>Snapshots>manage snapshot), I deleted all the snapshots. (When deleting snapshot on production VM be cautious, You may require it later), Whenever there is snapshot on VMware Virtual Machine, Hard disk cannot be extended.
Useful blogs on troubleshooting
RESOLVED : ADDING VIRTUAL HARD DISK GRAYED OUT ON VIRTUAL MACHINE
RESOLVED : FAIL TO DEPLOY OVF TEMPLATE - TASK CANCELED BY USER