If wanted, the password prompt can be removed using Microsoft’s CMAK (Connection Manager Administration Kit), selecting the "Advanced customization" checkbox and setting the HidePassword option in the [Connection Manager] section. Click on Drop down in CMAK Wizard for this feature.
Whether the Password box appears in the Connection Manager logon dialog box when using dial-up connections.
Edit the CMS file under the line: PasswordHandling
Create line: "HidePassword=1"
0 (default) = Display the box
1 = Do not display the box.
If the field is hidden, the data is considered optional.
- Do not edit any entry in the .cms file if it can be set by using the CMAK wizard, because the CMAK wizard may overwrite entries in the .cms file.
- If an entry is valid in both .cms and .cmp files, edit only the .cms entry.
- Make sure that locations are specified either as the full path or in reference to the location of the .cmp file.
More information here
An example below with the Microsoft password prompt removed.