I also had the same experience. Kept getting asked for the keychain login password (which no doubt was entered correctly) but it was constantly rejected.
Rebooting & restarting TurboTax did not help. Could not change access from "ask each time" to "all access to all applications" either.
But resetting the login password (main login screen for MAC). Reset to the same as the original password and now it worked in the TurboTax box.
Must be operating system version dependent. I solved this after lots of time trying everything.
So anyone experiencing this should try each suggested option in this thread. If the first one doesn't work, try the next one until something works. There should be a better answer (than trial and error) from the TT support staff.
