1. Click on Client Information on the navigation tree;
2. Scroll down to the Miscellaneous Info section;
3. On the line Prepared by, select 3 = Self-Prepared.

I am having the same problem.  I did enter that I am the self-preparer and still get the critical diagnostic.

@ghunter999-gmail That's because I misread the question, thinking the OP was asking about marking the return as self-prepared.

Instead you should do the following:

1. Go to General > Misc. Info./Direct Deposit;
2. Click on the Miscellaneous tab;
3. Scroll down to the Miscellaneous section; and
4. Under Designee/IRS Discussion, on the line Allow discussion: 1=yes, 2=no, 3=blank [Override], enter 3.