You can force an inventory check by doing the following
- Find and delete the mk_inventory.last.* file. This is the file that stores the last time the inventory process was run
- Go to the check_mk web interface and trigger / refresh the Check_MK HW/SW Inventory service.
Observe the Output of the check plugin entry in the service detail table for Check_MK HW/SW Inventory service. It should read a lot of entries.