Version: (using Devel) Installed from: Compiled sources If you don't have ksysguardd installed and run ksysguard, the graphs simply don't work and no informative error is given. It should tell the user that ksysguardd doesn't exist, and ideally even ask whether to install it.
100% agree. I took me a while to figure that this was the reason that my monitoring graphs were blank. From a user perspective, this is a bug, in my opinion. To give you more background information, my problem started with the inability to monitor CPU and RAM usage using plasmoids in KDE4. The CPU and RAM monitor plasmoid were simply empty. Upon investigation I found similar issues in ksysguard: i) in the system load tab, all graphs (cpu, memory, network history) were blank, and ii) when opening a new tab, the sensor browser showed a blinking entry: orange warning icon and "localhost". Installing ksysguardd fixed the issue. I now get graphs in ksysguard. ksysgraph really needs to detect when ksysguardd is not running and make it clear to the user that this is needed to plot graphs.
Also, ksysguard package information reads: "In addition to monitoring the local system, it can connect to remote systems running the KDE System Guard Daemon, which is in the 'ksysguardd' package." This is misleading because ksysguardd is used to monitor the local host too. The versions I am using are: kdebase-runtime 4:4.3.0-2+b2 ksysguard 4:4.3.0-3 ksysguardd 4:4.3.0-3