Why is the Last Boot-Up Time of a managed machine showing incorrectly?
ITMS 8.x
The Last Boot-Up time information in the database is updated when the last Full Inventory runs; as this inventory collects information on the last reboot event which occurred prior to the last Full Inventory being run.
The data for the Last Boot-up time is current as of the when the last Full Inventory ran, and the Inventory Policy schedules should be checked and you should verify that the Inventory policies completed successfully.
NOTE: This is the Sample SQL query that can be run ro check the last Boot-Up time and you can customize it according to your needs to show the data for the specific machines:
select
vc.[Name],
vc.[OS Name],
vc.[User],
os.[Last Boot Up Time]
from vcomputer vc
left join Inv_OS_Operating_System os on vc.Guid = os._ResourceGuid
where IsManaged = '1'
order by os.[Last Boot Up Time]