Negative inventory is one of the most common (and frustrating) issues teams run into, especially when you're exporting settlements to QuickBooks or reviewing an inventory report and see a negative quantity on an item. The good news: in ConnectBooks' inventory system (ConnectStock), every transaction can be traced from purchase to sale. Use the steps below to find the cause and fix it quickly.
Quick checklist (start here)
Find where it's negative. Open Reports, Inventory, Inventory Summary Report and note which warehouse (Local, In Transit, FBA) is negative for the item.
Check the listing and item mapping. In ConnectStock, go to Items, search for the item and click View Listings. Confirm:
All linked listings really belong to this SKU.
Multipack and group items are set up correctly (no double multiplying).
Units of measure are set up correctly for purchasing.
The listing's pack quantity matches how the item is bought.
Example of a mistake: If you buy an item as a 10 pack (without using Units of Measure) and also set the listing quantity to 10, a single sale could take off 10 × 10 = 100 units.
Check your FBA setup (if FBA is involved).
FBA Shipments: make sure all shipments from the inventory file start date are transferred, none are ignored, and they're posted to the right warehouse.
Beginning balances: make sure your file has beginning inventory adjustments for all warehouses as of the file start date:
a Local beginning adjustment
an FBA beginning adjustment
a second FBA adjustment after your in transit shipments have arrived, to account for all items that were in transit on the start date
If all of that looks good, go deeper with the steps below.
Step by step: trace the problem
1. Filter the Inventory Detail Report
Open the Inventory Detail Report.
Enter the item and filter to the warehouse that's negative.
You'll now see every transaction for that item in that warehouse, from the very start until now.
What to look for:
Is there a beginning balance? (For example, "Beginning Adjustment: 1,000 units".)
Ins and outs that don't make sense? Missing bills, unexpected adjustments, wrong FBA shipments and so on.
Warehouse mistakes on bills. This is a very common cause.
Never post a vendor bill directly to FBA. Receive into your Default (source) warehouse first. FBA shipments then move inventory to In Transit, and then to FBA.
Tip: Sometimes it's easier to export the report to Excel and sort by date or transaction type.
2. Fix the root cause
Depending on what you find:
Wrong listing mapping or pack size: Correct the listing. ConnectBooks recalculates all transactions on this listing. You just need to update the existing FBA adjustments to fix current counts.
Bill in the wrong warehouse: Edit or move the bill to Local and let the FBA shipment handle the transfer. You might need to redo the adjustments if this item's inventory was miscounted.
Missing bills or overstated adjustments: Enter the missing bills or correct the sales or adjustments.
Ignored FBA shipments: Click Transfer on the shipments. You might need to redo the adjustments if this item's inventory was miscounted.
If you still can't find it
Option A: Roll forward from your last reconcile date
Pick the last date your ConnectStock inventory matched reality (for example, July 1).
Run the Inventory Detail Report from July 1 forward for the item and warehouse.
Review each transaction after that date to see if anything looks off or if a transaction is missing.
Option B: No reconcile date? Create a new one.
If you don't have a checked baseline, you'll chase ghosts. So do this:
Physical count in Local: Post a new inventory adjustment to your local warehouse to match your actual inventory.
FBA Adjustment: Create a new FBA adjustment that matches Amazon as of the same date.
Clear Negative Inventory: If any items are still negative, go to ConnectStock, Adjustments and click Bulk Adjustment. Pick Clear Negative Inventory as the type, choose the warehouse and date, then click Import. A new adjustment opens, filled in for you. If you have no Amazon, Walmart or AWD stores, the button is called Clear Warehouse and goes straight to this.
From today on, watch the Inventory Detail Report to catch any new negatives quickly.
Special cases to check
FBA quirks
Amazon can receive too many or too few units on FBA shipments, and reports don't always add up perfectly. If In Transit or FBA stays negative (or oddly positive):
Go to ConnectStock, FBA Shipments, and open the Shipment Discrepancies tab. Reconcile all FBA shipment discrepancies.
Example: You sent 100 units and Amazon received 20. Reconcile the 80 unit difference based on Amazon's final outcome.
Multiple warehouses
Always isolate the issue by warehouse first. A healthy Local balance can hide a negative in FBA or In Transit.
Prevention tips (so it doesn't happen again)
1 source of truth for packs: Set the pack size once and make listings match. Avoid double multiplying quantities.
Receive to Local first: Post all vendor bills to Local, never to FBA.
Use transfers, not shortcuts: Let the FBA shipment move stock from Local to In Transit, and then to FBA.
Close and reconcile FBA shipments regularly: Clear discrepancies promptly.
Keep a regular reconcile schedule: Monthly (or more often), check Local, In Transit and FBA, and post adjustments as your baseline.
Check mappings after catalog changes: Any time you add group items, bundles or new listings.
Bottom line
Negative inventory always traces back to a specific transaction or setup: mapping or pack mistakes, bills in the wrong warehouse, FBA movements that weren't posted, or missing beginning balances. Follow the flow above (find the warehouse, check the mapping, trace the transactions) and you'll find and fix the issue quickly.
Frequently asked questions
Can I post a vendor bill straight to my FBA warehouse?
You shouldn't. Receive it into your Default (source) warehouse first. The FBA shipment then moves the inventory to In Transit and FBA.
When do I make the second FBA adjustment?
After your in transit shipments have arrived. It covers items that were in transit on the start date.
Where can I see every transaction for an item?
In the Inventory Detail Report. Filter it to the item and the warehouse that's negative.