> What was the complete pg_upgrade command you used?
"C:\Program Files\PostgreSQL\12\bin\pg_upgrade" -d "C:\Program
Files\PostgreSQL\9.4\data" -D "C:\Program Files\PostgreSQL\12\data" -b
"C:\Program Files\PostgreSQL\9.4\bin" -B "C:\Program
Files\PostgreSQL\12\bin" -U postgres -p 5432 -P 5435
>
>