Ok, this is weird. I'm trying to deactivate my old PS4 , however, the option to do it is greyed out. It won't even allow me to activate it as my primary console, saying that there's another PS4 activated on my account even though I only have 1 PS4. Any idea how I can fix this?
Yup, just did this tonight as I forgot to deactivate my old Ps4 before backing up and moving hard drives around.
So, go on your PC, log into your PSN account.
Enable 2 stage security and put in your mobile number, go through the process.
Once you have 2 stage set up, PSN then allows you to deactivate all consoles (as long as you have not done this in last 6 months).
Then make your new pro your primary...
DONE. If you want, you can now turn off 2 stage on PSN
However, if you have your old Ps4 still working then deactivate it in the account settings if you can.