What does it mean when if I received a LTR 2645C from the IRS?

It means they need more time to process your return. 

In my case it seems to mean that they have not received my employer's/bank's W-2/1099 data yet.

Thanks, I got that.  My return was submitted mid-February, and I know of many people who submitted after mine and their refund was provided within a few weeks so really the question is for what reasons might they need to have more time?  

Thanks. I can understand this. I will look into it, but I don't believe this is my situation.

is there an IRS phone number on the notice? then call them. They are the only ones that can answer your question. 

The letter does say "if you have questions you can call  ." But it does not include a phone number, just an empty space between the word call and the sentence ending period. That's why I figured to ask the community to see about potential causes of such a letter. 

@jag1966

To  call the IRS:IRS:  800-829-1040  hours 7 AM - 7 PM local time Mon-Fri

Listen to each menu before making the selection.

First choose your language. Press 1 for English.

Then do NOT choose the first choice re: "Refund", or it will send you to an automated phone line.

Instead, press 2 for "personal income tax".

Then press 1 for "form, tax history, or payment".  

Then press 3 "for all other questions."

Then press 2 "for all other questions."  It should then transfer you to an agent.

 

 

Thanks!