Problem description

inSync Client 5.9.9 has the following launch and activation issues on Ubuntu:

When launching inSync Client 5.9.9 on Ubuntu version 18.04.x having KDE interface, it crashes.

inSync Client 5.9.9 launch from terminal fails with the below error:

 inSync Cannot mix incompatible Qt library (version 0x40807) with this library (version 0x40805) Aborted (core dumped)

Cause

inSync Client is not compatible on KDE versions of Ubuntu and is only supported with GNOME or UNITY.
A Qt5 platform theme or style plugin which has not been re-compiled against the latest version of Qt5 . These usually use Qt private headers which depend on an exact version of Qt and not just a matching name.
inSync Client is shipped with its own Qt library, which the client calls at the launch time. However, since the kernel refers to its own build of Qt library during the client launch, the client shows an error. Hence, inSync Client is works as designed but the error message and issue arises from the OS kernel itself.