Speed up File.Exists for non existing network shares

I have to check if a set of file paths represent an existing file.

It works fine except when the path contains a network share on a machine that's not on the current network. In this case it takes a pretty long time (30 or 60 seconds) to timeout.

Questions

• Is there a way to shorten the timeout for non existing network shares? (I'm certain that when they do exist they'll answer quickly, so a timeout of 1 sec would be fine)

• Is there any other way to solve this issue without starting to cache and making the algorithm more complex? (ie, I already know these X network shares don't exist, skip the rest of the matching paths)

UPDATE: Using Threads work, not particularly elegant, though

public bool pathExists(string path) 
{
    bool exists = true;
    Thread t = new Thread
    (
        new ThreadStart(delegate () 
        {
            exists = System.IO.File.Exists(path); 
        })
    );
    t.Start();
    bool completed = t.Join(500); //half a sec of timeout
    if (!completed) { exists = false; t.Abort(); }
    return exists;
}

This solution avoids the need for a thread per attempt, first check which drives are reachable and store that somewhere.

Experts exchange solution:

First of all, there is a "timeout" value that you can set in the IsDriveReady function. I have it set for 5 seconds, but set it for whatever works for you.

3 methods are used below:

1. The first is the WNetGetConnection API function that gets the UNC (\servername\share) of the drive
2. The second is our main method: The Button1_Click event
3. The third is the IsDriveReady function that pings the server.

This worked great for me! Here you