I just installed a fresh new install of PostgreSQL-10.5-1-win64-bigsql
Once installed I wanted to add the PostGIS extension ran: CREATE EXTENSION postgis;
Got error message could not find C:\PostgreSQL\pg10\share\postgresql\extension\postgis.control
I found the file at this location C:\PostgreSQL\pg10\share\extension\
So I thought I could just copy the postgis.control into the directory where it was being looked for and ran the create extension and got this: ERROR: extension "postgis" has no installation script nor update path for version "2.4.4"
Best Answer
When installing PostGres Database, the installer would install Stack Builder which is used to add extensions. Is is easier to use this method. Search for Stack Builder in Windows, run it and just add PostGIS from there.