Cannot deserialize the JSON array (e.g. [1,2,3]) into type ' ' because type requires JSON object (e.g. {"name":"value"}) to deserialize correctly

Your json string is wrapped within square brackets ([]), hence it is interpreted as array instead of single RetrieveMultipleResponse object. Therefore, you need to deserialize it to type collection of RetrieveMultipleResponse, for example :

var objResponse1 = 
    JsonConvert.DeserializeObject<List<RetrieveMultipleResponse>>(JsonStr);

If one wants to support Generics (in an extension method) this is the pattern...

public  static List<T> Deserialize<T>(this string SerializedJSONString)
{
    var stuff = JsonConvert.DeserializeObject<List<T>>(SerializedJSONString);
    return stuff;
}

It is used like this:

var rc = new MyHttpClient(URL);
//This response is the JSON Array (see posts above)
var response = rc.SendRequest();
var data = response.Deserialize<MyClassType>();

MyClassType looks like this (must match name value pairs of JSON array)

[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
 public class MyClassType
 {
    [JsonProperty(PropertyName = "Id")]
    public string Id { get; set; }

    [JsonProperty(PropertyName = "Name")]
    public string Name { get; set; }

    [JsonProperty(PropertyName = "Description")]
    public string Description { get; set; }

    [JsonProperty(PropertyName = "Manager")]
    public string Manager { get; set; }

    [JsonProperty(PropertyName = "LastUpdate")]
    public DateTime LastUpdate { get; set; }
 }

Use NUGET to download Newtonsoft.Json add a reference where needed...

using Newtonsoft.Json;

Can't add a comment to the solution but that didn't work for me. The solution that worked for me was to use:

var des = (MyClass)Newtonsoft.Json.JsonConvert.DeserializeObject(response, typeof(MyClass)); 
return des.data.Count.ToString();

Deserializing JSON array into strongly typed .NET object