I have the same exact problem with Turbo-Tax activation.
Get this message:
"All Available activations for that code have been used. Error code:603"
Initially it would ask me to activate every time I would launch turbo-tax,
finally started to give the 603 error message.
It was originally installed on two computers, due to the repeated error codes I uninstalled from one computer and still getting the 603 error message repeatedly.
Tried the usual "disconnect the network cable wired/WiFi when starting the Turbo-Tax, disable anti-virus/anti-malware/firewall software check, restart modem/router, uninstall and re-install turbo-tax -- none of that worked.
Total waste of time trying to resolve this, turbo-tax technical support very difficult to get to, no resolution so far, complete and total waste of time. Extremely disappointed with Intuit and Turbo-Tax.
