Infor SyteLine4 min readNetray Engineering TeamUpdated March 4, 2025

How to Resolve SyteLine MRP Exceptions

MRP exceptions in SyteLine are action messages generated when the planning engine detects misalignment between supply and demand. These exceptions include reschedule-in, reschedule-out, cancel, and expedite messages that require planner review. Left unaddressed, MRP exceptions cascade into late orders, excess inventory, and production disruptions. This guide covers how to systematically analyze, prioritize, and resolve MRP exceptions using SyteLine's planning workbench and targeted SQL queries against the MRP tables.

Understanding MRP Exception Types and Priority

SyteLine generates six primary exception types: Expedite (supply needed earlier), Defer (supply needed later), Cancel (supply no longer needed), Release Planned (convert planned order to firm), Reschedule In (move supply date earlier), and Reschedule Out (move supply date later). Access exceptions through the MRP Exception Messages form or query directly with SELECT * FROM dbo.mrp_exception_msg WHERE except_code IN ('E','D','C','R') ORDER BY due_date ASC. Prioritize exceptions by impact: Expedite and Reschedule In affect customer delivery dates and should be addressed within 24 hours. Cancel and Defer exceptions affect inventory carrying costs and can be reviewed weekly.

Query MRP exceptions: SELECT except_code, item, due_date, qty FROM dbo.mrp_exception_msg ORDER BY due_date
Prioritize Expedite (E) and Reschedule In (R) exceptions first as they directly impact customer delivery
Review Cancel (C) exceptions weekly to prevent excess inventory buildup and reduce carrying costs
Use the MRP Exception Messages form with filters by planner code to distribute workload across planning team

Root Cause Analysis for Recurring Exceptions

Recurring MRP exceptions signal systemic planning parameter issues rather than one-time demand changes. Run a frequency analysis query: SELECT item, except_code, COUNT(*) as frequency FROM dbo.mrp_exception_msg GROUP BY item, except_code HAVING COUNT(*) > 3 ORDER BY frequency DESC. Items appearing more than 3 times typically have incorrect lead times, safety stock levels, or lot sizing rules. Open the Item Planning Parameters form for flagged items and verify the planning lead time matches actual supplier or production lead time. Check order quantity modifiers including minimum order qty, maximum order qty, and order multiple — overly restrictive lot sizing generates excessive reschedule exceptions.

Run frequency analysis on mrp_exception_msg to identify items with recurring exceptions (threshold: >3 occurrences)
Verify planning lead times in Item Planning Parameters match actual supplier delivery performance
Review lot sizing rules (min qty, max qty, order multiple) that may force suboptimal order quantities
Check safety stock levels against actual demand variability using standard deviation of past 12 months consumption

Processing Exceptions and Validating MRP Results

After analyzing exceptions, process them through the MRP Action Messages form or use the APS Planning Workbench for visual scheduling. For bulk reschedule operations, use the Process MRP Messages utility to automatically apply recommended date changes to purchase orders and production orders. Before processing, validate MRP results by checking the MRP Pegging inquiry to confirm demand-supply relationships. Run SELECT item, trans_type, due_date, qty, order_num FROM dbo.mrp_peg WHERE item = 'YOUR_ITEM' to see the full pegging chain. After processing exceptions, regenerate MRP for the affected items to verify the exceptions clear and no new cascading exceptions appear.

Use Process MRP Messages utility for bulk reschedule operations on purchase and production orders
Validate pegging chains: SELECT trans_type, due_date, qty, order_num FROM dbo.mrp_peg WHERE item = 'ITEM'
Regenerate MRP for affected items after processing to verify exceptions clear without creating new ones
Document exception resolution patterns to build a planning parameter tuning checklist for quarterly review

Frequently Asked Questions

How many MRP exceptions per planner is considered manageable?

Best practice is under 50 active exceptions per planner per day. Organizations with over 200 exceptions per planner typically have systemic planning parameter issues. Start by fixing the top 20 items by exception frequency, which usually accounts for 60-70% of total exceptions. Quarterly lead time and safety stock reviews prevent exception buildup over time.

Should I use net change or regenerative MRP to clear exceptions?

Use net change MRP for daily processing as it only recalculates items with changes since the last run, completing in 15-30 minutes versus 2-4 hours for full regeneration. Run full regenerative MRP weekly during off-hours to reset the planning baseline. After major parameter changes affecting more than 50 items, a full regeneration is recommended to capture cascading effects.

Why do MRP exceptions reappear after I process them?

Reappearing exceptions indicate the root cause was not addressed. Common reasons include lead time mismatches where the planning lead time differs from actual, demand changes from new sales orders or forecast updates arriving after processing, and supply constraints like vendor capacity limits. Check if new demand was entered after your last MRP run and verify planning parameters match reality.

Key Takeaways

1Understanding MRP Exception Types and Priority: SyteLine generates six primary exception types: Expedite (supply needed earlier), Defer (supply needed later), Cancel (supply no longer needed), Release Planned (convert planned order to firm), Reschedule In (move supply date earlier), and Reschedule Out (move supply date later). Access exceptions through the MRP Exception Messages form or query directly with SELECT * FROM dbo.mrp_exception_msg WHERE except_code IN ('E','D','C','R') ORDER BY due_date ASC.
2Root Cause Analysis for Recurring Exceptions: Recurring MRP exceptions signal systemic planning parameter issues rather than one-time demand changes. Run a frequency analysis query: SELECT item, except_code, COUNT(*) as frequency FROM dbo.mrp_exception_msg GROUP BY item, except_code HAVING COUNT(*) > 3 ORDER BY frequency DESC.
3Processing Exceptions and Validating MRP Results: After analyzing exceptions, process them through the MRP Action Messages form or use the APS Planning Workbench for visual scheduling. For bulk reschedule operations, use the Process MRP Messages utility to automatically apply recommended date changes to purchase orders and production orders.

Overwhelmed by MRP exceptions in SyteLine? Netray's supply chain consultants can tune your planning parameters and build exception management workflows. Contact us for an MRP health assessment.

Talk to an Expert See a Demo

Related Resources

Infor SyteLine