Error "Unable to load DLL 'STLib.dll'" when starting the patch catalog
The following error will appear if the requirements for the patch catalog for SCCM Addon have not been considered
In detail, the vcredist 2015 was not installed here
https://www.microsoft.com/en-US/download/details.aspx?id=48145
Once both vcredist 2015 versions have been installed, the patch catalog can be used as usual.