Something's not quite rightYou need to activate this item before updating the quantity.

Hi there. Let's work together to get rid of that error so you'll be able to continue performing your task.

To clarify, did the error appear when you were trying to edit an item? Also, have you inactivated the item and tried to adjust the quantity? Any additional information you can add is a great help so I can provide an accurate solution.

The error you getting indicates that an item you're trying to use or update is inactivated in QBO. To verify this by following these steps:

1. Select the Sales menu and choose Products and Services.
2. Then, select the Funnel icon and select All under Status.
3. Click Apply.
4. From there, check and look for the item in question.
5. If you see the Make Active option under the Action column means that this is inactivated. 
6. Select it to activate it. 

Once done, you can now continue doing your tasks. If you want to adjust the inventory quantity, please refer to this article: Adjust inventory quantity on hand in QuickBooks Online. 

Additionally, I've added this helpful resource that you can use as a guide in tracking your inventory: Set up and track your inventory in QuickBooks Online.

I'm always here ready to lend a hand if you have other concerns managing your inventory. Have a good day ahead, and stay safe.