I recently took over a database in which the previous dba had set a number of table fields to act as lookup displaying combo boxes. This is a horrible thing to do, IMHO, and since users should never directly have access to tables, and should be working through forms, there is absolutely no reason for this in the first place. Now not wanting to have to go through hundreds of tables and countless fields resetting this property manually, I decided to write a simple function to perform this cleanup for me. Hopefully this might help someone else out with this issue.

'---------------------------------------------------------------------------------------
' Procedure : RemoveAllTableLookupCboLst
' Author    : Daniel Pineault, CARDA Consultants Inc.
' Website   : http://www.cardaconsultants.com
' Purpose   : Loops through all the tables in a database and removes/resets the Lookup
'             Display Control property to reset it to a simple textbox rather than a
'             combo box or listbox.  Never needed as users should never access tables
'             directly!
' Copyright : The following is release as Attribution-ShareAlike 4.0 International
'             (CC BY-SA 4.0) - https://creativecommons.org/licenses/by-sa/4.0/
' Req'd Refs: None required
'
' Usage:
' ~~~~~~
' Call RemoveAllTableLookupCboLst
'
' Revision History:
' Rev       Date(yyyy/mm/dd)        Description
' **************************************************************************************
' 1         2013-05-17              Initial Release
' 2         2019-02-23              Updated Header
'                                   Updated Error Handler
'---------------------------------------------------------------------------------------
Function RemoveAllTableLookupCboLst() As String
    Dim db              As DAO.Database
    Dim td              As DAO.TableDefs
    Dim t               As DAO.TableDef
    Dim fld             As Field
 
    On Error GoTo Error_Handler

    Set db = CurrentDb()
    Set td = db.TableDefs
    On Error Resume Next
    For Each t In td    'Loop through each table
        If Left(t.Name, 4) <> "MSys" Then    'Don't mess with system tables!
            For Each fld In t.Fields    'loop through each field
                If fld.Type = dbText Then    'Only modify Text fields
                    fld.Properties("DisplayControl") = acTextBox
                End If
            Next fld
        End If
    Next t

Error_Handler_Exit:
    On Error Resume Next
    If Not td Is Nothing Then Set td = Nothing
    If Not db Is Nothing Then Set db = Nothing
    Exit Function

Error_Handler:
    MsgBox "The following error has occurred" & vbCrLf & vbCrLf & _
           "Error Number: " & Err.Number & vbCrLf & _
           "Error Source: RemoveAllTableLookupCboLst" & vbCrLf & _
           "Error Description: " & Err.Description & _
           Switch(Erl = 0, "", Erl <> 0, vbCrLf & "Line No: " & Erl) _
           , vbOKOnly + vbCritical, "An Error has Occurred!"
    Resume Error_Handler_Exit
End Function