Farmerswife auto-generates Inventory Numbers for your Equipment either manually or via the Object Import functionality in the Object Manager.
The Inventory Numbers need to consist of only numbers, no combination of letters and numbers possible with this option.
(Inventory Number: 9045556 = works, LHE_123456 = doesn't work)
Enable this functionality in the Server Setup > Objects tab > Auto Number Inventory Number: Yes.
Manual creation of Objects in Object Manager
Once the setting is enabled in the Server, farmerswife will auto fill a new Inventory Number into the Inventory Number field adding a +1 to the last Inventory Number given.
Please remember a combination of letters and numbers in the Inventory field won't work with this functionality.
Auto generation of Inventory Numbers via the csv import into the Object Manager
In the cvs file, the Inventory Number column is the U column, see picture. In this column please add the word: "auto" (without the brackets) to activate the auto generation of the Inventory Number while the new equipment is being imported into the Object Manager.
This will also work if you import Objects with Accessories or Groups.