Difficult start with pgAdmin. First blank window. Then 'acsii' codec can't decode byte ...

Dear all,

I just tried (wanted to try) pgAdmin for the first time and was
surprised to run into two problems.

* System is Windows 7 64 bit
* I downloaded the binary for pgAdmin 4 v1.1 from
https://www.pgadmin.org/download/windows4.php
* After installation I did a reboot
* Then I started pgAdmin from the start menu and the following happened:
* I do not know whether this is server or desktop deployment, I guess
it's Desktop

1. The pgAdmin splash screen showed up. Some seconds later, I got a
blank (white) window with standard decorations (x in the upper right,
etc.). I waited for about one minute, but the window remained blank.

2. Then I closed the window and startet pgAdmin again. Splash screen
... and ... this time the window was created properly. So I decided to
add a server. Right click on Servers -> Create -> Server. I filled in
the name, then went to the connection tab. I filled in the hostname, a
username and a password and clicked on save. A window pops up, the
title being "Error saving properties: GONE" with the message "'ascii'
codec can't decode byte 0xc3 in position 64: ordinal not in range
(128)". There are no fancy characters neither in any name nor password.

Then I checked the documentation for prerequisites, hints, but didn't
find anything related to my problem within a couple of minutes.

I wanted to look into the "issue list" as per web page
https://www.pgadmin.org/support/issues.php but apparently I need to
create an account first to see the list (which I didn't do, yet) :-/

I'm having a difficult time getting started with pgAdmin. Hope you
can help me here. Did I miss anything? If yes, please point me to the
corresponding documentation.

Best Regards
Michael