Can't type into Terminal

I don't know if it might have something to do with my Prefferences --> General - "Shell open With" which currently reads "/bin/CustomShellStaff" under the "Command (complete path)", even though "Default Login Shell" is selected.

Your suspicion is correct. That custom shell does not exist on a new Mac or one that has been properly configured for resale.

Please follow What to do before you sell, give away, or trade in your Mac .... Those instructions describe the necessity to completely erase the Mac, so start there. Step 6.

I completed a product refresh yeaterday to my R6100 Netgear wifi modem. It was fruitful. This am the point at which I turned on the PC I get the message that the Genie quit suddenly . In the screen it says Exemption Type: EXC_CRASH (SIGABRT). I don't have a clue if this aides however I can't get the typical genie box .

Yes, that would have been preferable, but since the seller did not properly prepare the Mac for sale, that task now falls to you. That is, unless you care to return it to have it done right or just get a refund. You will encounter continual problems with that Mac until those instructions are followed.

I signed in with another record on my machine and a similar thing occurs. I'm confused. The Apple partners are befuddled. I'm trusting somebody here can unstump this entire wreckage.

[Edited by Host]

Try this:

For "Shell opens with", click the bottom option and instead of what it says now type

"/bin/tcsh" (without the quotes).

Now quit and restart Terminal.