If there is no cheque specification in your active data directory then likely one was never created (possibly because one was not needed due to the fact that you were only writing manual cheques.

In AP open Maintain Specifications (under the Maintenance menu). Once open then under its File menu select Open Template. There are a number of templates to choose form. You may need to investigate a number of them until you find one close to what you want. From there is can be modified to fit your need.

Once you have the specification you will need to edit your Bank setup and assign the specification.

The error message is from attempting to edit the GL account number assigned to your bank. This is not necessary if all you are trying to do is add a specification.

If you are not familiar with this process you should contact your Adagio dealer for assistance.