So here's my problem and the solution that I arrived at to resolve it.
As often is the case you have your ISE deployment hosted in a vSphere environment; you manage to lock out the CLI admin account which cannot be reset through the GUI. You have to follow the instructions here:-
Now if like me your VM is installed with a large size memory, i.e. 64G then you may find the following error message appear when you select the correct option during the reset procedure:
A quick Google on this error will tell you this is related to the Linux Kernel trying to talk to the Extended memory range. Instead of boring you with all the things I tried I will cut to the chase. The work-around!
1) Power off your vm
2) Edit the vm settings and resize your memory down to 2G (below the extended memory range) This achieves the same as disabling PAE
3) Fire up your vm booting off the install media, and follow the menu instructions
4) Once you are done resetting your CLI password, power off the vm.
5) Edit the vm settings and restore your memory sizing to 64G (in my case) or whatever you decided to use when you installed in the first place.
You are done. Have a nice day
