C#: Finding directories with *.avi files

Hi

I'm trying to find all the directories that contain an *.avi file so I can move the directory
Doesn't matter if other files type exist in the same directory

In the code bellow I'm finding every directory even with no avi

           string[] Dirs = Directory.GetDirectories(Root, "*", SearchOption.TopDirectoryOnly);
            foreach (string Dir in Dirs)
            {
                string NewDir = "";
                string[] Files = Directory.GetFiles(Dir, "*.avi", SearchOption.TopDirectoryOnly);

                // If a no avi file in Dir Files should not be  null  ??

                if (Files != null ) //|| Files.Count() >= 1)
                {
                    NewDir = avi_files + Dir;
                    string OldDir = Root + "\\" + Dir;
                    if (!Directory.Exists(NewDir))
                    {

                        //   Directory.Move(OldDir, NewDir);
                        Console.WriteLine("OldDir: {0} NewDir: {1} ", OldDir, NewDir);
                    }
                }
 
           }

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The first Dir dose not have an *.avi file but in the "Immediate window"

Files != null
true

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That means Files has an avi file ??

as you can see in the code i've tried different methods

var files = Directory.EnumerateFiles(Root, "*.*", SearchOption.AllDirectories)
                    .Where(s => s.EndsWith("*.AVI") || s.EndsWith("*.avi"));

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