I've used this for years and never had a problem. No recall where I got it.
I run it on startup in autoexec macro.
Code:
Public Function AddTrustedLocation()
On Error GoTo err_proc
'WARNING: THIS CODE MODIFIES THE REGISTRY
'sets registry key for 'trusted location'
Dim intLocns As Integer
Dim i As Integer
Dim intNotUsed As Integer
Dim strLnKey As String
Dim reg As Object
Dim strPath As String
Dim strTitle As String
strTitle = "Add Trusted Location"
Set reg = CreateObject("wscript.shell")
strPath = CurrentProject.Path
'Specify the registry trusted locations path for the version of Access used
strLnKey = "HKEY_CURRENT_USER\Software\Microsoft\Office\" & Format(Application.Version, "##,##0.0") & _
"\Access\Security\Trusted Locations\Location"
On Error GoTo err_proc0
'find top of range of trusted locations references in registry
For i = 999 To 0 Step -1
reg.RegRead strLnKey & i & "\Path"
GoTo chckRegPths 'Reg.RegRead successful, location exists > check for path in all locations 0 - i.
checknext:
Next
MsgBox "Unexpected Error - No Registry Locations found", vbExclamation
GoTo exit_proc
chckRegPths:
'Check if Currentdb path already a trusted location
'reg.RegRead fails before intlocns = i then the registry location is unused and
'will be used for new trusted location if path not already in registy
On Error GoTo err_proc1:
For intLocns = 1 To i
reg.RegRead strLnKey & intLocns & "\Path"
'If Path already in registry -> exit
If InStr(1, reg.RegRead(strLnKey & intLocns & "\Path"), strPath) = 1 Then GoTo exit_proc
NextLocn:
Next
If intLocns = 999 Then
MsgBox "Location count exceeded - unable to write trusted location to registry", vbInformation, strTitle
GoTo exit_proc
End If
'if no unused location found then set new location for path
If intNotUsed = 0 Then intNotUsed = i + 1
'Write Trusted Location regstry key to unused location in registry
On Error GoTo err_proc:
strLnKey = strLnKey & intNotUsed & "\"
reg.RegWrite strLnKey & "AllowSubfolders", 1, "REG_DWORD"
reg.RegWrite strLnKey & "Date", Now(), "REG_SZ"
reg.RegWrite strLnKey & "Description", Application.CurrentProject.Name, "REG_SZ"
reg.RegWrite strLnKey & "Path", strPath & "\", "REG_SZ"
exit_proc:
Set reg = Nothing
Exit Function
err_proc0:
Resume checknext
err_proc1:
If intNotUsed = 0 Then intNotUsed = intLocns
Resume NextLocn
err_proc:
MsgBox Err.description, , strTitle
Resume exit_proc
End Function