I have a subform which causes the error message:
The LinkMasterFields property setting has produced this error: 'the object doesn't contain the Automation object 'TblContracts."

Does anybody have any idea what this really means, and how to fix it? Everything seems to work fine, other than the fact that this error message pops up every time I try to go to my subform, and also every time I open the main form or switch records.

Any help would be greatly appreciated, Thanks

Delete the Master/Child links then rebuild them by clicking on the button with the 3 dots just to the right of the Master and Child link fields.

I have already tried many times to delete the master and cild link fields, and I have re-built them many times both on my own, and by pressing the build button. In addition to this, I have re-created the subform many times both by using the sub-form field, and by dragging another form onto my page.

Thank you for your help. I have finally figured out a way around the problem...although I still do not understand why it happens in the first place.

I created a text box on my main form whith the datasource being the field I am linking to. Then on the masterLink area, I call that text box. This seems to fix the problem, although again, I don't understand why this works but I can't set the master link directly to the field on the underlying table.

I know this post is very old, but since I just had the same problem in Access 2007 and this post is highly ranked by Google, here is a possible solution:

I had a query underlying the form which used the tbl.* to query all the fields in the table and then tbl.field which was sorted ascending. I was trying to link my subform to tbl.field, but Access counted two instances of the field and could not decide which one to link to.

I used the Query Design window to remove the tbl.* part of the query and simply dragged in all the individual fields. The problem solved without having to create a separate text box.