Just wanted to shed a bit of hope on this particular subject. I filed 1-13-17, accepted 1-17-17, was starting to wonder as nothing had changed for a couple weeks, on 2-1-17 my WMR bar disappeared, so I thought I was nearing a refund deposit. WRONG! On 2-6-17 I received letter 4883C requiring me to call and verify ID, I was on hold for 50 minutes and was asked the questions Robert mentioned, very simple to answer if you have your W-2s, all told the call took 1 hour 20 minutes. The gal on the phone mentioned at the end it would be up to 9 additional weeks before I see a refund in my bank. All my hopes and dreams were crushed, I generally like to use my refund to buy toys for my hobbies (PC build, pickup upgrades, gaming accessories, etc.) and I had everything picked out lol but now I was totally crushed. Anyway, the impatient part of me made sure to check the status everyday, multiple times although I know it's pointless because it updates once a day at 3AM my time, so I checked it at 3:04 Saturday morning, this was 2-11-17, to my surprise my bar had reappeared and I had a refund date of 2-15-17. Granted, at the time of writing this I haven't received my refund, but hope has been restored and it looks like I will get my refund much earlier than I feared. Ultimately, I believe the cause for verification is a result of my online bank recently changing partner banks, and my routing/account numbers have changed since last year.
So, hopefully my story has inspired hope for those receiving this letter, I have been doing taxes with TurboTax for a few years now and have never had a problem or gotten a letter from the IRS, so I was a bit worried when handling the situation but everything seems to have worked out in the end.
Edit: I wanted to mention. I did not claim EITC or ACTC and had no code when my bar disappeared. I.e. no PATH or code number, it just said the same thing as before, but with no progress bar ("your tax return has been received and is being processed etc."). My tax return was just a run of the mill return from full-time employment.
Update: So, I have been checking the SBTPG website to see when they send my refund over to my bank (you can check that here
https://taxpayer.sbtpg.com/login if you filed with TurboTax). My refund was sent on Tuesday morning (2-14-17) at around 5:30 AM to my bank, nothing in my account all day Tuesday, this morning (Wednesday 2-15-17) my refund was deposited into my account and available at around 3:30 AM and I am a happy camper. I hope anyone going through the nightmare of verification has as good of luck as I've had. Keep your heads up tax payers, it could get better. Good luck!
