I'm having the same problem. I followed the instructions provided here for editing form 4797:
<a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/3129871-how-do-i-edit-or-delete-sale-of-business-property-form-4797">https://ttlc.intuit.com/questions/3129871-how-do-i-edit-or-delete-sale-of-business-property-form-4797</a>
Clicked "Jump to" link in search results, then "Sales of business or rental property" (first checkbox under "Any other property sales"), then "No" on the "Sales of Business or Rental Property" page, then "Yes" on the "Sales of Other Business Property" since I sold at a loss.
However when I get to the next screen"Tell Us About Your Sale" and select "Section 1244 small business stock", I get this message:
"Do not report small business stock sales (Section 1244) here. Enter them in the stock sales topic of investments."
The problem with entering them as a stock sale under Investments is I didn't get a 1099-B and there's no option to select a "Special situation" as referenced here:
<a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/3813780-i-am-eligible-for-a-section-1202-exclusion-how-do-i-indicate-that">https://ttlc.intuit.com/questions/3813780-i-am-eligible-for-a-section-1202-exclusion-how-do-i-indicate-that</a>
My guess is that either the interfaces have changed since these answers were posted, or they're using a version other than Premiere, or there's a bug.
I called Support and was put on hold for 45 min. as they searched for an answer. Ultimately they transferred me to another support desk where I was told by an automated message that the response could only be provided by the TurboTax Live service for another $100. I opted "No" and was hung up on.
I'm going to do a bit more digging and will follow up here if I find anything.
Following up on my comment to the first answer: The only way I was able to enter a 1244 stock loss was by purchasing the CD/Download version of Turbotax and going into Forms mode to add/edit Form 4797 directly. According to this answer: https://ttlc.intuit.com/replies/7177886
?" TurboTax CD/Download versions Deluxe, Premier, and Home/Business all include Form 4797."
And here's some more info on Forms mode including how to move your return from the online version to the desktop version:
https://ttlc.intuit.com/replies/4225672
Also worth noting from here: https://ttlc.intuit.com/questions/2577481-why-would-i-use-forms-mode
"It's OK to switch to Forms Mode if you want to look at a form or two, but constantly switching back and forth between Forms Mode and the interview has been known to cause problems and data corruption."