There are two report templates in the Sitka_templates → Inventory folder on the Reports screen.

Inventory - Scanned Items Count by Shelving Location

This report counts the items that have been checked in/out or otherwise had their status changed (including being checked out, marked missing or lost) during the inventory period. The date when you started taking inventory should be entered as the Copy Status Changed Time when running the report. The numbers are broken down by shelving locations.

Inventory - Un-scanned Items

This report generates a list of items that should be on the shelf but were not checked in/out or otherwise had their status changed during the inventory period. When running the report use the date when you started taking inventory for the Copy Status Changed Time, the shelving location(s) in which you took inventory and the "on shelf" statuses Reshelving and Available.

You can use this report to search for the listed items. You can also upload the barcodes from this report into the Item Status screen and set the items to Missing.