There are some restrictions for WebDAV in different Operating systems.
When you try to set up a web folder by "adding a network location" or "mapping a network drive" through My Computer, you can get an error message saying that either "The folder you entered does not appear to be valid. Please choose another" or "Windows cannot access… Check the spelling of the name. Otherwise, there might be…". These errors may appear when you are using SSL or non-SSL.
To fix this problem, do as follows:
Windows 7
Go to Windows Registry Editor.
Find a key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlset\services\WebClient\Parameters.
Select BasicAuthLevel (you might create it as REG_DWORD key if it does not exist) and change its value to 2.
Reboot.
Windows 8
Go to Windows Registry Editor.
Find a key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlset\services\WebClient\Parameters.
Select UseBasicAuth (you might create it as REG_DWORD key if it does not exist) and change its value to 1.
Select BasicAuthLevel (you might create it as REG_DWORD key if it does not exist) and change its value to 2.
Reboot.
If you have Microsoft Office 2010 or Microsoft Office 2007 applications installed on a client computer, try to access an Office file that is stored on a web server that is configured for Basic authentication from the client computer. The connection between your computer and the web server does not use Secure Sockets Layer (SSL). When you try to open or to download the file, you experience the following symptoms:
The Office file does not open or download.
You do not receive a Basic authentication password prompt when you try to open or to download the file.
You do not receive an error message when you try to open the file. The associated Office application starts. However, the selected file does not open.
To enable the Basic authentication on the client computer, do as follows:
Click Start, type regedit in the Start Search box, and then press Enter.
Locate and then click the following registry subkey:
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\Internet
On the Edit menu, point to New, and then click DWORD Value.
Type BasicAuthLevel, and then press Enter.
Right-click BasicAuthLevel, and then click Modify.
In the Value data box, type 2, and then click OK.