Lansweeper 5.0 pulls the uptime from WMI, specifically from the systemuptime field of Win32_PerfFormattedData_PerfOS_System. Note that a machine's scanned uptime value reflects the uptime
at the time of the last successful scan. Uptime information will only be accurate if your machines have
recently and
successfully been rescanned. The "last seen" dates listed in the Summary tabs of your computer webpages must be recent.
Lansweeper 5.1,
currently in beta, provides more detailed uptime information. It scans shutdowns, reboots and other uptime events from the client machine's event viewer.