pgadmin4 : postgresql application server could not be contacted.

Question

I have installed PostgreSQL 9.6.2 on my Windows 8.1. But the pgadmin4 is not able to contact the local server. I have tried several solutions suggested here in stackoverflow

Answer 1

Have you recently installed a new version of pgAdmin ?

This issue (and the misleading message) is simply due to the fact that old versions of pgAdmin are unable to read the settings saved by a newer version of pgAdmin !

Make sure you're starting the right version of pgAdmin (your shortcuts are likely to point to the old version !) and/or uninstall the old version: the upgrade wizard doesn't do it for you !