Do I need to mail in form 8949 if the e-filed form has only one transaction with dates of the acquisition and sale?

I think you mean you reported one investment sale and it appeared on form 8949 and you want to know if you need to mail a copy of that form to the IRS even though you have e-filed your tax return. If so, then no, you don't need to mail anything in this instance.

It sounds like this is the case, but to be sure here is the 8949 list with the one and only transaction:

Am I correct in assuming that given the above form was the one that was e-filed I don’t need to mail in a paper form? 

Correct, you don't need to mail in the Form for 1 transaction. You would have been prompted before you efile if you needed to mail anything to the IRS.

See guidance below :

If you’re paper-filing your return, Form 8949 will simply be included with all your other tax forms when you print them out.

If you're e-filing, you only need to mail the IRS a copy of your 8949 (along with Form 8453) if you entered sales section totals for one or more sales categories (instead of each individual sale) and one of the following is true:

• The sales category for one or more summaries is something other than box A (short-term covered) or box D (long-term covered), or
• The box A or box D summary includes adjustments (typically listed in boxes 1f or 1g on your broker statement)

Form 8949

@jbhkt7 

The funny thing is, at the end after I e-filed, it did prompt me about mailing in forms, but when I clicked the link to print my forms, the pop up didn't load anything to print and said TurboTax encountered some sort of error. Perhaps it thought because I only had one transaction that I entered a summary entry, and this is a bug with the software?

Is there any way to tell within the software after e-filing if there any forms I need to mail to be 100% sure?

I'm fairly certain from what you guys have told me that I in fact do not need to mail in the form, but I want to definitively establish this before the three day mail in window is up (I filed 1 day ago).

@HopeS 

@ThomasM125 

Correct, you do not need to mail Form 8949 to the IRS.  To follow-up on the comments from @HopeS and @ThomasM125, sometimes taxpayers will prefer to report their transactions in summary fashion on Schedule D without also completing Form 8949.  Reporting in summary fashion on Schedule D without also completing and filing Form 8949 is acceptable provided certain conditions are satisfied.  Those conditions are as follows:  

• You received a Form 1099-B (or substitute statement) that shows basis was reported to the IRS and doesn't show any adjustments in box 1f or 1g; 
• The Ordinary box in box 2 isn’t checked;
• You don't need to make any adjustments to the basis or type of gain (or loss) reported on Form 1099-B (or substitute statement), or to your gain (or loss); and 
• You aren’t electing to defer income due to an investment in a QOF and aren’t terminating deferral from an investment in a QOF.

However, in your tax situation, you did complete and e-file Form 8949 with your return.  Thus, you do not need to separately mail Form 8949 to the IRS.  

@jbhkt7