JabRef 5.0.0-dev--2019-10-18----bc26c3ac5
Windows 7 6.1 amd64
Java 12.0.2

• [+] I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

Steps to reproduce the behavior:

1. When opening jabref a console starts with this error message
   ERROR StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath. Using SimpleLogger to log to the console...
2. Then Jabref opens still. I do not know what the effect of this error will be.
3. ...

Paste an excerpt of your log file here