Reference page: Active Directory – Sample Scripts (Excel/VBA) 

While processing User Account put the following code in the beginning of operations to disable it.

'Disable user account.
objUser.AccountDisabled = True

'Save info
On Error Resume Next
objUser.SetInfo
boolRC = (Err.Number <> 0)
On Error GoTo 0

If boolRC Then
'recovery code

End If

And enable it back once you’re successfully done.

'Enable user account
objUser.AccountDisabled = False

'Save info
On Error Resume Next
objUser.SetInfo
boolRC = (Err.Number <> 0)
On Error GoTo 0

If boolRC Then
'recovery code

End If

This way,  in case of an unhandled exception that breaks execution of a script, any User Account that wasn’t properly processed will remain disabled and easily noticeable.