If I make a mistake doing inventory, how can I go back and correct it?

You can go back and edit any item's count by continuing your current inventory session or reopening a previous one.

Go to the Take Inventory page, then either click Reopen Last Session or Resume Current Inventory Session, depending on if you've already ended the session or not. From there, click on the location that has the item(s) you want to edit, and then update its count. Finally, click on Finish Location - your changes are automatically saved.