Several friends and clients have told me that they have received IRS Letter 2645C and don't know what to do. The letter says, in part 

"Thank you for your inquiry of (date).

We-re working on your account. However we need an additional 60 days to send you a complete response on what action we are taking on your acc ount. We don't need any further information from you right now.

If you have questions you can call or write, etc.

None, nor I on their behalf, submitted any questions or requestsf, etc to the IRS. They have all received a refund, or paid taxes due, for the year in question.

Any ideas on what this is all about?