How to fix frequent WebDav “path not valid” errors

After experiencing some intermittent “path not valid” and very frustrating errors trying to open different types of files from my SharePoint server I’d had enough. I had to know what was going on.

Here’s the behaviour I was seeing. I had used a certain machine to edit SharePoint files in applications such as WordPad and Paint in the past so I just jumped on it and tried to open a file from SharePoint in MS Paint and it would just keep failing with “path not valid”. I tried the same file from another machine and it worked fine. So back the first machine with the error and I tried images from other directories on the same server, they all failed with “path not valid”. I then started trying to open different file types with different applications. What I found was quite surprising (to me anyway). I was able to successfully open a .txt file from SharePoint in WordPad and from that point on my original image files that failed to open in Paint started working fine.

Now I already knew that WebDav had a few dependencies and that the WebClient service had to be running, but I had initially dismissed this as a possible cause as I knew I’d been working fine with WebDav on this machine only a couple of days prior… it turned out this was a bad assumption to make.

What I wasn’t expecting was that there are some actions you can do that will start the WebClient service if it’s not already running. As I discovered, one of those actions it to use WordPad to try and open a file on a UNC path. A bit of digging around also revealed that putting a UNC path in Windows Explorer will cause the WebClient service to start as well.

Here’s the proof:

Now trying to open the original image file (that failed) in Paint works fine.

So I learned my lesson, even though it’s something I thought I already knew. If you are making use of WebDav MAKE SURE the WebClient service is set with a startup type of “Automatic”.