Error when opening Sharepoint 2010 document library in the Windows Explorer view
When your document library contains more than 10.000 items (or a different limit set in your registry as explained below) you might receive the following error message when opening the library in the Sharepoint 2010 Windows explorer view:
\\sitecollection\DavWWWRoot\subsite\documentlibrary is not accessible. You might not have permissions to use this network resource. Contact the administrator of this server to find out if you have access permissions.
A device attached to the system is not functioning.
Sadly this problem doesn’t have anything to do with permissions or devices that are not attached or not functioning so the message is misleading. The message is probably used for a variety of issues.
In my case the error showed up because my document library contained more then 10.000 items and the limit set in the registry was 10.000 on the computer i was working on. When the number of items in the document library exceeds the number specified in the registry it will throw the error and you will not be able to access the explorer view.
Luckily after changing the limit from decimal 10000000 (for 10.000 items) to for example decimal 20000000 (for 20.000 items) the problem was solved and i could open the view as expected. See the registry setting below: