How can I uncheck that there are more than one items in box 7?

If you did not delete the 1099-R and re-enter it you need to do that.

To delete a specific form in TurboTax Online you can follow these steps:

1. Within your return, click on Tax Tools in the black menu on the left side of the screen.
2. Click on Tools.
3. Click on Delete a Form. 
4. Scroll down to your form and click Delete.
5. Under Federal in the black menu bar click Wages & Income to get back into your tax returns.
6. Proceed entering/reviewing your return.

To do this in TurboTax Desktop you can follow these steps:

1. Within your return, click on the Forms icon in the upper right of the screen to switch to Forms mode.
2. Scroll down in the menu bar on the left and select your form.
3. Click the Delete Form button at the bottom left of the preview screen.
4. Confirm the deletion then click the Step-by-Step icon in the upper right of the screen.
5. Proceed entering/reviewing your return.

@sjames1994