Basic or Professional?  I have Professional and I've been using standard letters all year.  While the federal return is open, click on the Tools menu and you should see an option for letters.  Follow the prompts from there. 

Click on the state and then go back to the federal or exit client and then go back into client.  It’s a minor glitch that happens periodically this year.

I also have this problem, but if I go back and request an update to software the client letters does reappear and I can then choose the letter I wish to print for the client.

It’s some weird glitch in the program. If you exit the file and reopen it, they should be back to normal or if you switch over the state and then back to the federal they should be available.

For me, "periodically" is every single return.  Also, I can't print the letter with the return for pdfs because it's not even an option under the "choose items to print" button in the print dialogue box.