I thought that I had the funds from my previous 401k rolled over to my new 401k, but it turns out that never happened thanks to some paperwork mistakes. Once I received my 1099-R saying I was the recipient of those funds, I called the retirement company and found out they mailed me the check in July 2017 but I never received it. They will be reissuing the check to me, and I plan on depositing it into my current 401k, but I don't know how to claim or report it. To the IRS it looks like I cashed out even though that was never my intention and those funds will ultimately go into my 401k.
Yes, you will still just enter this Form 1099-R as a rollover distribution.
Because you received a 1099-R, the IRS will also have received a copy of this 1099-R. You will need to report this 1099-R distribution on your tax return but none of it will be taxable. Just make sure that when you are reporting this information into TurboTax that for the question "What Did You Do With The Money From (your retirement fund)?", answer "I moved the money to another retirement account (or returned it to the same retirement account)" (See Screenshot)
If the IRS contacts you about this Form 1099-R distribution, just send them your explanation of the circumstances and show the steps that you took once you realized the original rollover distribution did not occur as planned.
To enter 1099- R information in TurboTax, log into your tax return (for TurboTax Online sign-in, click Here and click on "Take me to my return") type "1099r" in the search bar then select "jump to 1099r". TurboTax will guide you in entering this information.