Hello there, i_cleaning.
Here are a few possible reasons why you're unable to merge a checking account:
- Parent account you are merging has an existing sub-accounts.
- Merging sub-accounts that are not on the same parent account.
- Accounts have different Types.
To check more of the account limitations, you can view this article: How to merge accounts, customers, and vendors.
I'm just a few clicks away if you have more questions or concerns about QuickBooks. Thanks.