Hi Jason,

I haven't seen anything specific to this Windows Feature Update and Sage 300, but the following sites talk about the update and problems it has caused - they may help.
https://wccftech.com/and-it-begins-all-the-windows-10-version-2004-known-issues-list/

https://www.zdnet.com/article/windows-10-2004-new-update-fixes-all-these-problems-says-microsoft/

Some general 'slow Sage' tech tips that you can  to go though:

• Check the PATH and the Customization Directories (inside Sage Admin Services folder), check the server and paths referenced.
  PATH - Start/Run/CMD/Enter/PATH/Enter. Must be only one reference to the correct Sage runtime folder , something like:

                   Data;C:\Progs\Sage\Sage Accpac\RUNTIME;

                  You can see the correct runtime folder under Sage / About menu/ System info

• And confirm that anti-virus software is properly configured to only have the server check itself and for the workstations to not check the Sage binaries on the network.
  
  
• You may have DNS issues - one for I.T.
  
  
• You should install all Sage Updates for your version - one for your Business Partner to assist with.
  
  
• You can run RVSPY while Sage opens - it will show you what it is doing at the time . Start menu / Sage / RVSPY

if you do find a solution please come back and let us all know. It will also be useful to let the community know your Sage 300 version and Product update, plus the server Windows version and MS-SQL version.