Should I block it?
No, this file is 100% safe to run.
 
 PE file structure
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Show functions  | 
Import table
mscoree.dll
DllMain
 
     
    
        Newtonsoft.Json.dll
Json.NET by Facebook (Signed)
| Version:    | 4.5.9.15308 | 
| MD5:    | cd74401890a1135b4995b505dad859dc | 
| SHA1:    | b97bc26abb0e236d0a7202aeae5555c7e379feef | 
| SHA256:    | 580c0486c6af7a83c62b61f4731b2b9e4426d1f03a62959e68dd42efafd00bdc | 
Overview
newtonsoft.json.dll is loaded as dynamic link library that runs in the context of a process. This is typically installed with the program Facebook Messenger 2.1.4651.0 published by Facebook. The assembly utilizes the .NET run-time framework (which is required to be installed on the PC). The file is digitally signed by Facebook which was issued by the VeriSign certificate authority (CA).
Details
| File name: | newtonsoft.json.dll | 
| Publisher: | Newtonsoft | 
| Product name: | Json.NET | 
| Description: | Json.NET .NET 2.0 | 
| Typical file path: | C:\users\user\appdata\local\facebook\messenger\2.1.4651.0\newtonsoft.json.dll | 
| File version: | 4.5.9.15308 | 
| Size: | 389.92 KB (399,280 bytes) | 
| Certificate | 
| Issued to: | Facebook | 
| Authority (CA): | VeriSign | 
| Effective date: | Tuesday, June 19, 2012 | 
| Expiration date: | Saturday, June 20, 2015 | 
| Digital DNA | 
| PE subsystem: | Windows Console | 
| File packed: | No | 
| Code language: | Microsoft Visual C# / Basic .NET | 
| .NET CLR: | Yes | 
| .NET NGENed: | No | 
More details
Programs
The following program will install this file
Facebook Messenger is an instant messaging service and software application which provides text and video communication. Like Facebook's web-based Chat feature, it supports the open-source XMPP protocol, connects primarily between Facebook users and synchronizes with the website. Among its features is a "ticker" similar in function to the sidebar of friend activity seen by Facebook website users. At the time of release, "chatting with m...
 
Distribution by Windows OS
| OS version | distribution | 
| Windows 7 Home Premium | 
31.58% | 
 | 
| Windows 7 Professional | 
15.79% | 
 | 
| Microsoft Windows XP | 
15.79% | 
 | 
| Windows 7 Ultimate | 
15.79% | 
 | 
| Windows Vista Home Premium | 
10.53% | 
 | 
| Windows 8 Pro | 
5.26% | 
 | 
| Windows Vista Home Basic | 
5.26% | 
 | 
Distribution by country
United States installs about 42.11% of Json.NET.
Distribution by PC manufacturer
| PC Manufacturer | distribution | 
| Toshiba | 
33.33% | 
 | 
| MSI | 
33.33% | 
 | 
| Acer | 
16.67% | 
 | 
| Hewlett-Packard | 
16.67% | 
 |