How do I return a stock part from a posted service invoice in Sage 100 Contractor?

Enter a credit in 11-2 with the part at a negative quantity and an Inventory Location. Once the total is negative the Reference# box appears; enter the original invoice number there. If it does not appear, save the credit and apply it in 3-3-1 Cash Receipts.

Free Guide: Inventory in Sage 100 Contractor

Inventory in Sage 100 Contractor, every screen and every posting

Most Sage 100 Contractor companies cost parts straight to jobs. The day you start keeping stock on a shelf, the inventory module has rules that are not obvious from the screens. This guide walks one part through its whole life so you can see exactly what to enter and what Sage posts.

14annotated screenshots

6tasks, start to finish

5errors explained and fixed

Six everyday tasks, each shown with the journal entry behind it

The guide follows one example part through Sage's demonstration company: it becomes a stock item, is purchased into inventory, is sold on a service invoice, is issued to a job, comes back from the job, and is credited back from a service invoice. For every step you get the screen to fill in and the 1-3 Journal Transaction Sage posts, so you can check your own postings against it.

1Make a part a stock item. The one checkbox in 9-2 Parts, why you have to save before other screens see it, and which parts should stay unflagged.

2How stock gets into inventory. Purchase orders and payable invoices for stock lines, and why a freshly flagged part still has nothing to issue.

3Sell a stock part on a service invoice. What Sage posts automatically: receivables, income, tax, material cost and the inventory relief at average cost.

4Allocate a stock part to a job. 12-2 Inventory Allocation, the 4-Shipped status, and the posting that moves cost from the shelf to the job.

5Return a part from a job to stock. The Destination column, the reverse posting, and why returns matter for job cost.

6Return a part to stock from a service invoice. Open versus posted invoices, negative-quantity credits, and the Reference# box that only appears once the total goes negative.

7Troubleshooting. "Part is not a valid stock item", allocations that will not save, shelf stock that shows nothing on hand, the missing Reference# box, and quantities that do not move.

8Quick reference. Every task, screen and posting on one page.

Office staff who enter invoices, and the person who moves the parts

Written for accounting and office staff who already work in 4-2 Payable Invoices and 11-2 Work Orders, and for the shop or warehouse person who issues and receives parts. No prior use of the inventory module is needed. Screenshots come from Sage 100 Contractor 2026, Canadian edition; the mechanics are the same in the US edition.

If you are planning to move existing shelf stock into the inventory module, the guide also explains why that is a one-time project (count, decide stock items, load opening balances, reconcile to the ledger) rather than a transaction, and what to have ready before you start.

Three questions the guide answers

Why does Sage 100 Contractor say a part is not a valid stock item?

The part's Stock Item box in 9-2 Parts is not ticked, or was ticked but not saved. Tick it, save, then close and reopen 12-2 Inventory Allocation. Screens that were already open do not see the change until they are reopened.

Why will an inventory allocation not save when the part is a stock item?

The part has no quantity on hand. Flagging a part does not put the parts you already own into inventory; quantity only arrives through a stock purchase or an opening-balance load. Section 2 and section 7 of the guide cover both routes.

How do I return a stock part from a posted service invoice?

Enter a credit in 11-2 with the part at a negative quantity and an Inventory Location. Once the total is negative the Reference# box appears on the Invoice Details tab; enter the original invoice number there. If it does not appear, save the credit and apply it in 3-3-1 Cash Receipts. Section 6 shows the posting.