I installed KDevelop 5.1.0 on an up to date Solus install shows the following error popup at startup.
Unable to create io-slave. Cannot talk to klauncher: The name org.kde.klauncher5 was not provided by any .service files
As I'm clearly not using KDE I ignored this at first. But opening any project fails with the following message:
Unable to load the project file /home/san/Projects/UnrealEngine/UE4.kdev4.
The project has been removed from the session.
When starting the kdevelop from the terminal you'll see a related issue whenever you try to open an project.
kf5.kio.core: couldn't create slave: "Cannot talk to klauncher: The name org.kde.klauncher5 was not provided by any .service files"
Having a quick chat with kfunk on #kdevelop he indicated this warning is probably the cause of kdevelop failing.