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Demand & Replenishment

Safety stock, reorder points, coverage groups and the buffer the planning engine plans TO but never recomputes.

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PillarFoundational guide

Dynamics 365 runs your MRP. Why is your inventory still wrong?

Master planning in Dynamics 365 is a calculation, not a decision. Microsoft ships the engine and leaves four replenishment-policy choices to you — coverage segmentation, safety stock method, forecast netting and time fences.

Muhammad Mudassir12 minJul 31, 2026
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Continue the path

Ordered by chapter. Each post stands alone but builds on the one before it.

Chapter 1

If you run Dynamics 365 SCM on-premises, do you have a supported MRP engine?

You have a running master planning engine on-premises, and it is the deprecated one — Planning Optimization does not support on-premises deployments. What "supported" means for the engine you are left with is described three different ways across three Microsoft pages. Here is each wording, quoted, and what each of the three honest options costs.

7 minRead
Chapter 2

What can Planning Optimization actually not do in 2026?

Microsoft's fit-analysis page currently marks three rows as Future wave — sales line reservation using explosion, intercompany planning execution, and requirement types for skills, courses, certificates and titles. But that page answers a narrower question than the one people ask, four other Microsoft pages carry real limits it never lists, and on three features Microsoft's own pages disagree with each other.

9 minRead
Chapter 3

Why does your MRP produce twelve thousand action messages?

Because the volume is an output of your coverage configuration, not a measurement of how wrong the plan is. Four settings decide the count, and Microsoft documents every one of them — coverage segmentation, negative days, the time fences on the master plan, and turning action messages off where the answer is always "do nothing".

9 minRead
Chapter 4

Time fence or time freeze — which one is deleting your planners' work?

Two features in the Dynamics 365 demand planning app have near-identical names and opposite jobs. A time fence stops people editing a forecast. A time freeze stops the recalculation overwriting what people edited. Only one of them is on by default, and it is not the one that saves your adjustments.

7 minRead
Chapter 5

Which forecast algorithm should you use for intermittent demand?

In the Dynamics 365 demand planning app you do not pick an algorithm for intermittent demand. Croston's method is not selectable — it is a fallback the best fit model reaches for, it only exists inside a preview version of best fit, and Microsoft's preview terms say preview features are not meant for production use.

8 minRead
Chapter 6

Why does your plan look right in month three and absurd in month one?

The near month is wrong because the forecast is not being consumed by the orders that arrived against it, so master planning covers the forecast and the orders. Four settings decide the netting, and two current Microsoft pages describe the carry-forward rule in opposite terms.

8 minRead
Chapter 7

Is DDMRP in Dynamics 365 actually free?

A qualified yes. Microsoft states Supply Chain Management "includes DDMRP with no additional license fees" — but DDMRP requires the Planning Optimization Add-in, which requires a Supply Chain Management licence, a tier-2 or higher Lifecycle Services environment, and a cloud deployment. The licence is the cheap part; the decoupling-point analysis is not.

8 minRead
Chapter 8

Should master planning use finite or infinite capacity?

Infinite everywhere, finite on the constraint, and the capacity time fence as the control in between. Turning finite capacity on globally on day one fails for reasons Microsoft's own documentation states plainly.

8 minRead
Chapter 9

Why does auto-firming fire at the wrong time under Planning Optimization?

Because Planning Optimization fires auto-firming on the order date — the start date — while the deprecated engine fired on the requirement date, the end date. Microsoft states both on two pages. A firming time fence carried across from the old engine still has lead time baked into it, so it firms weeks of orders early on day one.

7 minRead
Chapter 10

Why is your supplier OTIF ninety-eight percent when deliveries are late?

Because you are measuring against the last confirmed date, and the vendor moved it three times. Dynamics 365 stores one confirmed date per line and overwrites it. The honest measure is the first confirmed date plus a change count, and both are recoverable.

8 minRead
Chapter 11

Requirement, Period, Min/Max or Decoupling point — which coverage code for which item?

Microsoft's coverage settings page lists six coverage codes, not four — Manual, Per requirement, Per period, Min/Max, Priority and Decoupling point — and three Microsoft pages disagree on the names. Here is what each one does, which items Microsoft says each fits, and where the recommendation is ours rather than Microsoft's.

9 minRead
Chapter 12

Demand planning app or master planning — where does the forecast actually live?

Neither one owns it. The demand planning app calculates the forecast, master planning consumes it, and the object of record between them is a forecast model in Supply Chain Management. Here is the hop, the fields on both sides, and why "are we up to date" is a two-part question with two different version numbers.

9 minRead
Chapter 13

There is no S&OP module in Dynamics 365 — so what do you build?

Dynamics 365 Supply Chain Management documents no feature area called sales and operations planning. It supplies the demand engine, the supply engine and the capacity check. The consensus layer is the build, and it belongs on Power Platform rather than in the ERP.

9 minRead
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Read the writeup. Now ship the system.

Cognilium engineers ship the architectures behind these articles for enterprise teams. If you're mid-build on demand & replenishment, talk to us.