Here in this NG, on the Quicken website support center, and on the msn

How to Merge Two Bank Accounts in QuickBooks First you’ll want to go to the Chart ofAccounts and select the bank account that you want to be gone. Next, edit this account and make the spelling of the name be the exact as the one you are keeping. (A pop up box will open with a message “This name is already being used. This video shows you how to merge 2 bank accounts into one if you've been using 2 by accident and there should only be 1. Be careful as this cannot be undone!

Quicken Users group, there are various discussions of how to transfer
information, accounts, or entire data files from one Quicken file to
another. So far as I can tell, these are all elaborations of the
basic QIF export / import procedure.

When I try this procedure, the data and transactions in certain
accounts transfer just fine. However, try what I might, the
transactions (checks written) in one of the checking accounts and the
transactions in a money market fund (checks drawn on the fund) will
not transfer. (Interestingly, the deposits in the checking account do
transfer. Also interestingly, another checking account transfers
completely without a hitch.)

In all the poking around I have done, two notable things have struck
me.

First, I find no one else who mentions having such a problem.

Second, Intuit customer support bulletin KB ID#: 1174b entitled
'Moving information between Quicken data files' (available on their
website) addresses the question 'How do I transfer information,
accounts, or entire data files from one Quicken file to another?' and
gives extensive detailed instructions.

Midway, it says: 'Important: QIF import is available only for asset
and liability accounts (including house and vehicle), credit card
accounts, and cash accounts. . . . QIF import is not available for
checking, savings, 401(k), or any other brokerage accounts.'

That seems to be saying pretty clearly that QIF will not import
checking account transactions (nor money market account transactions,
if such an account is a 'brokerage' account). Several Intuit customer
support bulletins lay out the same procedure, but only that one
contains the caveat.

If it is true that you can't transfer checking or 'brokerage'
accounts, it is puzzling to me that one of my checking accounts
transferred successfully. Further, it is remarkable that none of the
extensive posts here on this NG or in the msn group on the subject of
merging files / exporting-importing data / marrying, etc. even mention
such an enormous catgegory of data that can't be moved via QIF.

Combine Quicken Files

Does anyone here have any suggestions, enlightenment, explanations,
education, or thoughts that might help. I just need to get the data
and transactions in two separate Quicken files (both v. 2004)
transferred into one file.

Merge Two Quicken Accounts

Thanks for any assistance.