First time using turbo tax. I claim my son like always and we are now filing his taxes like always and they are rejecting his saying someone claim you.

It's possible that his return is being prepared without marking that someone else can claim him on his taxes. 

To make the adjustment and refile, follow these steps:

1. Open the tax return and select 'MY INFO' from your menu

2. Select the EDIT option (pencil) next to filers name

3. Scroll to question #3 and select 'YES' for the option someone else can claim me as a dependent on their tax return. 

4. Work through the rest of the section, review, and refile.