Master Child link being broken.

[efrazier]

We have a database we converted to 2007 from 2003. The main form
contains two subforms. One subform is working fine, the other not so
much. When the database is filtered, the second subform appears to
lose the master child link. Existing data in the subform does not
appear, and we cannot add data to it - 'invalid use of null' error
appears.

On the subform I have the ID field that is being linked to from the
Master form. It is usually set to not visible, but I made it visible
for troubleshooting. In unfiltered usage the ID field shows the linked
ID from the Master form correctly. But when the filter is applied
that field shows '(New)'.

On other oddity. If, after applying the filter, I view the form in
Design View, then back to Form View, without changing anything, the
subform works correctly, and will continue to do so while in the
filter. But setting another filter brings the problem back.

 

[Anne]

From my experience, the error message of 'invalid use of null' leads back to
the data. Perhaps in the conversion, something did not convert properly and
there are errors in the underlying query. Check out the query data for
errors.