Download a plugin assembly (DLL) from Dynamics 365 CRM.

 CRM does not allow direct download of the DLL file from the UI. However, there are several ways to retrieve the plugin DLL from the CRM environment. we achieve this requirement using XrmToolBox.  

• Open XrmToolBox.
• Install and open Assembly Recovery Tool.
• Connect to your Dynamics CRM instance.
• It will list all deployed assemblies.
• Select the assembly and click Download.

Connect D365 Environment 

Configuration ==> Tool Library ==>Search "Assembly Recovery Tool" and install.

Tool==>Assembly Recovery Tool.

Double click on "Assembly Recovery Tool" all Assemble file will be appear. 

Select "Assemble "and  click on "Export to Disk "

Note :- All Assemble file store under "pluginassembly" entity.