pgAdmin4 - Query Tool stuck "Initializing the query execution!" on localhost

I seem to have a problem using the Query Tool on a local database. When I try to execute any query (for example SELECT 1), the tool just hangs on initializing it for a few minutes, after which pgAdmin outright crashes. Interestingly enough, when I download the result as CSV, I get the correct data. Also, on a remote server, the Query Tool works just fine for me.

Any ideas what might be causing this issue on localhost?

I'm running the desktop version on Windows 8.1 and my local db version is: PostgreSQL 9.3.5, compiled by Visual C++ build 1600, 32-bit