Thanks for your efforts. I have it working to my satisfaction, applying
work-arounds in the VBA code to cover all contingencies. Users can run
multiple or repetitive merges from buttons on an Access form, and they will
all coexist in the same Word instance as separate docs. In this particular
app, the data sources are hard-wired in the VBA code, and the code opens the
datasource after opening the doc, so it doesn't matter if the doc loads with
source attached or not. In other apps, if the user would need to select the
source, I plan to present a drop down (in Access) for the user to pick from,
then have Access open the doc & attach the source. Here's my code:
Public Sub WordMerge(MergeDoc As String, Query As String, OutDoc As String)
   ' Use late binding to accomodate various versions of Word lib
   Dim Doc As Object

   ' Varnames beginning "g" are global
   On Error Resume Next
   'Get instance of Word if already running
   Set gWord = GetObject(, "Word.Application")
   'If not running, create Word app
   If Err Then Set gWord = CreateObject("Word.Application")
   On Error GoTo 0
   gWord.Visible = True
   'Close this doc if open, to allow repeat of merge
   For Each Doc In gWord.Documents
       If Doc.Name = OutDoc Then
           Doc.Close
           Exit For
       End If
   Next
   gWord.Documents.Open FileName:=gsPath & MergeDoc
   gWord.ActiveDocument.MailMerge.OpenDataSource _
           Name:=gsDB, _
           LinkToSource:=True, _
           SQLStatement:="SELECT * FROM `" & Query & "`"
   gWord.ActiveDocument.MailMerge.Execute
   
   ' Execute has switched the active doc to the merge results
   gWord.ActiveDocument.SaveAs gsPath & OutDoc
   gWord.Documents(MergeDoc).Close SaveChanges:=True
   gWord.Documents(OutDoc).Activate
End Sub