Planners run MRP and the suggestions are missing, late, too small, too large, or for the wrong items.
When Sage X3 MRP produces missing, late, or wrongly sized suggestions, the cause is almost always data rather than the MRP engine — most commonly an incorrect item planning policy (lot-for-lot vs. fixed vs. reorder point), missing or wrong lead times, or demand MRP can't see. Start by verifying the item-site planning method and re-order quantities, then run an item-level pegging inquiry to confirm what demand MRP is actually reading.
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Why MRP results are always explainable
MRP in Sage X3 is deterministic. Every suggestion, and every suggestion that failed to appear, is explained by a demand, a supply, a product-site planning setting, or a parameter of the run itself. That makes this a tractable problem: when planners say the results are wrong, there is a specific element to find rather than a mood to manage.
The practical difficulty is that six or seven settings interact, and a planner sees only the output. Working through them in order, on one product-site with a clearly wrong result, is far faster than reviewing planning policy across the whole item master.
Why it happens
- Item planning policy set incorrectly (lot-for-lot vs. fixed vs. reorder point)
- Lead times missing or wrong
- Safety stock and minimum order quantity not configured
- BOM and routing missing or incorrect components
- Pegged demand from forecasts, sales orders, or dependent demand missing
- Site, warehouse, or status filters excluding stock
What produces wrong or missing results
The settings and tables named below are where to look when reviewing a case; they are reference points for diagnosis, not values to edit directly in the data.
Product-site planning settings
Reorder policy (MRP, reorder point, or none), suggestion type (purchase, work order, subcontract, inter-site), planner and buyer codes, lot sizing rules such as minimum, multiple, and economic quantity, safety stock, reorder lead time, and the horizon. A product that is not managed by MRP, or that has a blank suggestion type, simply produces nothing at all.
Demand that MRP cannot see
Sales orders that are not in a status MRP reads, forecasts loaded against the wrong site, or work-order component requirements never generated because the bill of materials alternative in use is not the one MRP reads.
Supply counted twice
Firm purchase orders, open work orders, and stale suggestions from previous runs all count as supply. Where suggestions are not deleted at the start of a run, or were left as firm planned orders, MRP believes the requirement is already covered.
Bills of materials and routings
Component lead time offsets, validity dates on the bill of materials, phantom handling, and which alternative MRP selects. These usually show up as timing problems rather than missing suggestions.
Run parameters
Site selection, horizon length, whether existing suggestions are reset, and whether master-scheduled products are excluded. Several "MRP is broken" cases are a run that never included the site or period the planner had in mind.
Lead times and calendars
Site calendars with non-working days, purchase lead time held on the product-supplier record rather than the product-site record, and safety lead times pushing dates outward.
Stock status and location
Stock sitting in a status MRP does not count, such as quality control or rejected, or in a location type excluded from availability.
Data volume and run performance
Large order and work-in-process tables, built up from years of unpurged planned orders, slow the run and can cause it to time out on a subset of sites.
The symptom pattern narrows this quickly. Nothing at all suggests planning settings or run scope. Dates in the past suggest demand inside the lead time. Quantities that look wrong suggest lot sizing, safety stock, or supply counted twice.
Diagnostic steps
- 1. Confirm the item plan policy
Open the item-site record and verify the planning method, lot-sizing rule, and re-order quantities.
- 2. Verify demand is visible to MRP
Run an item-level pegging or available-to-promise inquiry to see what demand MRP can actually see.
- 3. Check BOM and routing currency
An expired or inactive BOM or routing will silently break dependent demand for components.
- 4. Inspect lead time math
Sage X3 adds production, purchase, and queue/safety lead times. Off-by-one-week problems usually come from this.
- 5. Look at stock status filters
Stock in 'Quality' or 'Quarantine' status may be invisible to MRP depending on configuration.
Fixes
Reset planning parameters
Standardize planning methods across like items. Document which items are reorder-point, MRP-driven, or forecast-driven.
Refresh lead times
Recalculate purchase lead times from actual receipt history and production lead times from actual work order cycle time.
Repair master data
Inactivate obsolete BOMs and routings. Add missing components. Ensure routing operations match shop floor reality.
Tune safety stock and reorder logic
Use ABC analysis and demand variability to set safety stock instead of flat values.
Prevention
- Monthly review of MRP exception messages
- Quarterly planning parameter audit
- Master data discipline: BOM and routing changes go through engineering change control
When outside help is worth it
- Planners have lost confidence and are ordering outside the system
- Results differ between sites running what is supposedly the same configuration
- Run performance has become unacceptable for the planning cycle
- Bill of materials and routing data quality is suspect and nobody owns it
- The original implementation never tuned planning parameters beyond the defaults
PRH Consulting works on manufacturing implementation and optimization, planning parameter reviews, data-quality audits of bills of materials and product-site records, and performance work on work-in-process data volume.
Questions we get asked
Why is Sage X3 MRP not generating suggestions at all?
Usually the product-site is not managed by MRP, the suggestion type is blank, the demand is not visible to MRP, or the run parameters excluded that site or horizon. Check the run scope before the item settings.
Why are MRP suggestion dates in the past?
Because the demand falls inside the lead time. MRP cannot schedule earlier than today, so the suggestion lands on the run date or is flagged as late.
Why does MRP suggest more than we need?
Lot sizing rules — minimum quantity, multiple, or economic order quantity — safety stock levels, or stale suggestions from a previous run being counted as supply.
Does Sage X3 MRP consider safety stock?
Yes. Safety stock acts as a level to maintain, so it drives suggestions whenever projected stock would fall below it.
What is the difference between MRP and MPS in Sage X3?
MPS plans master-scheduled items, typically finished goods, while MRP explodes their requirements down to components. Products can be excluded from one or the other, which is a frequent cause of unexpected results.
Why does the MRP run take so long?
Data volume in planned and firm orders, the number of sites included, horizon length, or database performance. Purge and archive policy is usually the first thing to examine.
Related Sage X3 resources
- Sage X3 MRP and MPS consulting
Planning configuration, recovery, and optimization work.
- Troubleshooting slow Sage X3 performance
When the run itself is the problem.
- Sage X3 Standard Cost Setup and Cost Roll-Up
Bill of materials and routing quality affects costing too.
- Sage X3 Inventory Valuation and Stock-to-GL Reconciliation
Stock accuracy is the input MRP depends on.
- Sage X3 Mobile Warehouse and Barcode Scanning
Timely stock transactions keep planning credible.
- Manufacturing industry experience
Where planning work usually sits.
- ERP rescue
When planning has moved back to spreadsheets.
- Manufacturing consulting services
Planning, production, and costing configuration work.
- Manufacturing MRP optimization case study
Planning re-enabled after MRP had been abandoned.