SUMMARY I have a 512 GB drive in my system, about half of that is being used. Last night I connected a 1 TB drive over USB and then unmounted it with the eject icon in Dolphin. Now, system monitor's Disk overview tile says I have 1.1 TiB of used space and 1.4 TiB of free space. That's basically the sum of the disconnected external drive plus the internal drive. STEPS TO REPRODUCE 1. Connect external USB drive to system, then unmount it with the eject icon in Dolphin. OBSERVED RESULT System Monitor shows your disk space is higher despite the drive no longer being present. EXPECTED RESULT Calculate the overview based on what is actually mounted. SOFTWARE/OS VERSIONS Operating System: SteamOS 3.6.20 Build: 20241030.1 KDE Plasma Version: 5.27.10 KDE Frameworks Version: 5.115.0 Qt Version: 5.15.12 Kernel Version: 6.5.0-valve22-1-neptune-65-g9a338ed8a75e (64-bit) Graphics Platform: X11 ADDITIONAL INFORMATION df -h in the terminal shows the correct amount of disk space used and avail. The calculate button on properties for / in dolphin says "at least 128 TiB". Filelight scan is able to display that the drive is a 512 GB with half used.
Thank you for the bug report! However Plasma 5.27.10 is no longer eligible for support or maintenance from KDE; supported versions are 5.27. (LTS), and 6.2 (non-LTS) or newer. Please upgrade to a supported version as soon as your distribution makes it available to you. Plasma is a fast-moving project, and bugs in one version are often fixed in the next one. If you need support for Plasma 5.27.10, please contact your distribution, who bears the responsibility of providing support for older releases that are no longer supported by KDE. If you can reproduce the issue after upgrading to a supported version, feel free to re-open this bug report.
Rebooting the machine restored the disk space displayed to the correct amount. So it seems as if the bug is related to removable drive unmounts not communicating it clearly to another part of the system.