When a datafile is first synchronized to another Mac, or to a mobile device using iData Mobile Plus, iData Pro assigns a Sync ID to that datafile. Once a datafile has a Sync ID, its basic field structure can no longer be modified. That is, fields cannot be deleted, inserted, or moved (although they can be renamed).

If you need to change the field structure of a synced datafile, you must first remove its Sync ID.

Here are the instructions for doing this in a way that will not cause problems with copies of that datafile on other Macs or mobile devices (referred to as "devices", below).

1. Open the datafile in iData Pro 4.

2. Sync the datafile so that the version on the Mac is up-to-date. Use whichever sync methods you normally use.

3. To make a backup copy of the datafile, select Save As... under the File menu. In the Save dialog, type in a name that will permit you to identify it in case anything goes wrong with the procedure, then click the Save button.

4. This will result in the original datafile being closed, and the copy being opened, so close the copy and reopen the original datafile.

5. Select Remove Sync ID under the File menu.

6. When you see the alert window asking if you’re sure, click the Remove It button.

7. Select Modify Fields in the Fields sub-menu, under the Edit menu, and make all desired changes.

8. Once you are satisfied with all of the changes, save the datafile in iData Pro.

9. Delete the copy/copies of the datafile on your other device(s).

10. Back in iData Pro, select Save As New Sync File... under the File menu to move it to your other device(s). 

11. Check the other devices  to make sure that they contain the modified version.