Manufacturing Cloud: Sales Agreement forecast quantity edit fails with 'Your edits weren't successful' error

Work through the causes in order. Stop at the first one that applies.

Cause 1: Schedule being edited is a past schedule
1. Open the Sales Agreement [SalesAgreement] record and click the Agreement Terms tab.
2. Identify the schedule for which the edit failed and check its Start Date [StartDate] on the Sales Agreement Product Schedule [SalesAgreementProductSchedule].
3. If Start Date is earlier than today, the Forecasted Quantity for that schedule cannot be updated. Edit only schedules with a Start Date in the current or a future period.

Cause 2: Actuals Calculation Mode is locking schedule edits because Orders are linked
1. Navigate to Setup > Quick Find > Sales Agreements > Sales Agreements.
2. Review the Default Actuals Calculation Mode section. If it is set to "Automatically from Orders" or "Automatically from Orders Associated with Contracts", actuals on schedules linked to Orders are auto-calculated and related schedule fields are locked.
3. On the affected Sales Agreement, add the Actuals Calculation Mode [ActualsCalculationMode] field to the page layout if not visible: Setup > Object Manager > Sales Agreement > Page Layouts.
4. Open the affected Sales Agreement, set Actuals Calculation Mode to "Manual", and save. The Forecasted Quantity [ForecastedQuantity] / Forecasted Quantity Value [ForecastedQuantityValue] fields on the future schedule become editable.
5. If the business still tracks actuals from Orders, leave the org-level mode unchanged and instead use the Proposed Planned Quantity flow described in Cause 3.

Cause 3: Sales Agreement is Activated — edits to an Activated agreement must go through revision
1. Open the Sales Agreement and confirm Status [Status] = Activated.
2. On the Agreement Terms tab, edit the Proposed Planned Quantity [ProposedPlannedQuantity] / Proposed Planned Quantity Value [ProposedPlannedQtyValue] for the target future schedule instead of the live Planned Quantity field. The Sales Agreement moves to Under Revision (IsUnderRevision [IsUnderRevision] = true).
3. Submit the agreement for approval. On approval, the proposed values are applied and the agreement is reactivated.
4. To update Forecasted Quantity on a future schedule of an Activated agreement, edit Forecasted Quantity [ForecastedQuantity] directly on the future schedule row in Agreement Terms. If the row is read-only, confirm Cause 1 and Cause 2 do not apply and proceed to Cause 4.

Cause 4: User is missing the required permission
1. Navigate to Setup > Permission Sets > [User's permission set] > System Permissions.
2. Enable "Edit Actual Quantity of Sales Agreements Products" and save.
3. Confirm the user also has Read and Edit on Sales Agreement [SalesAgreement] and Sales Agreement Product Schedule [SalesAgreementProductSchedule].
4. Have the user log out and back in, then retry the edit.

Cause 5: Page layout is missing the decimal field
1. If the customer is entering a decimal value (for example 1.5) but the field on the layout is the integer Forecasted Quantity [ForecastedQuantity], the save fails silently with the generic error.
2. Navigate to Setup > Object Manager > Sales Agreement Product Schedule > Page Layouts and the Multi-Line Layouts for Sales Agreement Products.
3. Add Forecasted Quantity Value [ForecastedQuantityValue] (decimal) to the layout and remove or hide the integer field if decimals are required.
4. Verify the Sales Agreement's Decimal Scale [DecimalScale] is set high enough (0–6) for the value being entered. Decimal Scale only applies to agreements created after the org-level value was set; for older agreements, raise it on the agreement record itself if the field is exposed.

Confirm the issue is resolved by reopening the Sales Agreement, navigating to the Agreement Terms tab, editing the Forecasted Quantity for the previously failing future schedule (for example, February 2026), and verifying the value saves without the "Your edits weren't successful" error and the Total Forecasted Quantity recalculates.