URLResourceValue and setResourceValues Swift 3

Additionally to what TheEye provided, make sure your URL is a var and not a let.

That is what made my code work after migrating to swift 3.

The Xcode suggestion "Use struct URLResourceValues and URL.setResourceValues(_:) instead" is prompting you to write something like this:

let paths = NSSearchPathForDirectoriesInDomains(.libraryDirectory, .userDomainMask, true)

for dir in paths {
    print("the paths are \(dir)")
    var urlToExclude = URL(fileURLWithPath: dir)
    do {

        var resourceValues = URLResourceValues()
        resourceValues.isExcludedFromBackup = true
        try urlToExclude.setResourceValues(resourceValues)

    } catch { print("failed to set resource value") }
}

Please try.

NOTE

Please note that the file URL has to be a var - if it's a let you will get strange error messages (see comments).