URI formats are not supported - only local path works

In conjunction to what Dave posted, which is 100% correct, the 'File.ReadAllBytes' method does not directly support reading files from a URL. It's designed for reading files from local paths on your filesystem.

You need to use a different approach, involving a web request to download the file contents first. You can use the 'HttpClient' class to achieve this, the example below in C# as you did not specify what language you are using -

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        //The URL of the file you want to read...
        string fileUrl = "http://localhost/test.exe";

        try
        {
            using (HttpClient client = new HttpClient())
            {
                // .Send an HTTP GET request to your specified URL...
                HttpResponseMessage response = await client.GetAsync(fileUrl);

                //Check if your request was successful...
                response.EnsureSuccessStatusCode();

                //Read the content of the file as bytes...
                byte[] bytes = await response.Content.ReadAsByteArrayAsync();

                //Now you can work with the 'bytes' array as needed, for example, you can save it to a local file...
                File.WriteAllBytes("local_test.exe", bytes);

                Console.WriteLine("File downloaded and saved successfully.");
            }
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine($"An error occurred: {ex.Message}");
        }
    }
}

[EDIT]
If you want to minimize disk activity and keep the file download in memory without leaving a file trace on the disk, you can use the 'HttpClient' to download the file as a byte array -

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        // The URL of the file you want to read
        string fileUrl = "http://localhost/test.exe";

        try
        {
            using (HttpClient client = new HttpClient())
            {
                // Send an HTTP GET request to the specified URL
                HttpResponseMessage response = await client.GetAsync(fileUrl);

                // Check if the request was successful
                response.EnsureSuccessStatusCode();

                // Read the content of the file as bytes
                byte[] bytes = await response.Content.ReadAsByteArrayAsync();

                // Now you can work with the 'bytes' array as needed
                // For example, you can process the bytes in memory
                // without writing to a local file

                Console.WriteLine("File downloaded and processed in memory.");
            }
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine($"An error occurred: {ex.Message}");
        }
    }
}

i like that idea - when trying i get errors about Feature 'using declarations' is not available in C# 7.3. Please use language version 8.0

using VS 2019
just doing a proof of concept program and it's my first - kind of lost

here is what i have so far that works with local files

class Program
    {
        static void Main(string[] args)
        {
            var bytes = File.ReadAllBytes(@"..\..\..\..\Test\test.exe");
            CMemoryExecute.Run(bytes, @"C:\Windows\Microsoft.NET\Framework\v2.0.50727\vbc.exe");
            Console.ReadKey();
        }
    }
}