Regarding a large donation, for which we have an appraisal and already signed form 8283, there are conflicting instructions in TurboTax. On one screen regarding attaching signed appraisal statement, it says "You can e-file this return, however you must mail the appraisal with form 8453 which can be found with your forms when you finish your return." Then as I was finishing everything up it says I can't e-file because of an entry on form 8283. Other I have now seen in this form is saying no I can't file because of 8283. So why did the first screen say that I can e-file? Particularly when it referenced a form specifically for how to e-file and submit the required 8283 form???
Yes, you need to mail your return with Form 8283 if an attached appraisal is required, sorry.
I haven't seen other users post the conflicting info you received, so have no context for this, unfortunately. Some Form 8283's can indeed be Efiled.
An option would be to Efile without Form 8283, and amend later to add it, or edit your donations to Efileable ones, and amend later for the one requiring a written appraisal and mail.
Here's more info on Form 8283.