Checked. ContolSource's value is in the list of values, but Combo comes up blank.

OK - unless this combo is in a grid, the only reason that the combo would come up blank is that the value of the controlSource is not in its internal list - even though it may superficially look like it is. In this case you need to check the respective data types, etc. of the controlSource and RowSource to ensure they match. Verify BoundColumn and BoundTo to make sure that you are binding to what you think you are.

If the combo is in a grid, this is a known issue with RowSourceType 2-Alias and 6-Fields. The workaround is to change the RowSourceType to something else.