Symptom:

In Windows Vista or later version, after you map a WebDAV shared drive, such as a SharePoint document library, you are required to type your password every time you open it. Clicking the Remember Password checkbox seems to have no effect. Additionally, you get an Unable to connect to network drive message when you start the computer. This is particularly a problem when the WebDAV share is located outside of your local network (on the Internet).

Solution: 

When you check the Remember Password box, Windows is actually saving your password. You should be able to see it in your Credentials Manager Control Panel. The problem is that as a security feature Windows does not allow this password to be sent automatically (This only applies to WebDAV shares that are outside your local network.)

With a little registry editing, however, we can set the system to allow saved passwords to your external WebDAV servers.

Important: modifying registry incorrectly can cause damage to your computer, so always back up your registry first by using the export command with the registry editor.

Read the Microsoft Knowledge Base article here for more information. 

  1. Click Start, type regedit in the Start Search box, and then press Enter.
  2. Locate and then click the following registry subkey:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
  3. On the Edit menu, point to New, and then click Multi-String Value.
  4. Type AuthForwardServerList, and then press Enter.
  5. On the Edit menu, click Modify.
  6. In the Value data box, type the URL of the server that hosts the Web share, and then click OK.
    Note: You can also type a list of URLs in the Value data box.
    For more information, see the Sample URL list section in the Microsoft article.
  7. Exit Registry Editor.