The reason it is going to the first record in the recordset when no match is
found is because of this line:

   DoCmd.ShowAllRecords

The ShowAllRecords method does a couple of things, some of which you don't
really want to do. It removes any filtering on the form's recordsetand is
requeies the recordset.  A requery always takes you back to the first record
of a form recordset.

So, the question is is there any filtering on the form or the form's
recordset?  If not, maybe just removing that line will resovle the issue.  If
that doesn't do it, I would suggest rewriting the sub using more specific
code.  The code, as written, is one step better than macros, but is still a
long shot from precisely written code.

If you need help rewriting how the search is done, I would need to know the
name of the field in the form's recordset you want to search on.  But, as a
general way of doing a search, this may help.

This assumes the code is in the form module of the form you are searching:

'Performs the search using value entered into txtSearch
'and evaluates this against values in UNIT_ID field

Private Sub cmdSearch_Click()

'Check txtSearch for Null value or Nill Entry first.

   If Nz(Me.txtSearch), vbNullString = vbNullString Then
       MsgBox "Please enter a value!", vbOKOnly, "Invalid Search
Criterion!"
       Me.txtSearch.SetFocus
   End If
   Else
       With Me.RecordsetClone
'Use this if the table field Unit_ID is numberic
           .FindFirst "[Unit_ID] = " & .txtSearch                          
                   

'Use this if the table field Unit_ID is text
           .FindFirst "[Unit_ID] = """ & .txtSearch & """"

           If .NoMatch Then
             MsgBox "Match Not Found For: " & strSearch & " - Please Try
Again.", _
           , "Invalid Search Criterion!"
               txtSearch.SetFocus
           Else
               MsgBox "Match Found For: " & strSearch, , "Congratulations!"
               Me.Unit_ID.SetFocus
               Me.txtSearch = vbNullString
           End If
       End With
   End With
End Sub