Purchase Order By date is in the past

After our MRP run we are seeing some order dates for materials in the past yet we do not have allow historical dates set anywhere I am aware of i.e. MRP checkbox or Company Config > Production Tab > job.

And you are running regenerative?

We have been running regen for the past few runs and we have been seeing past po dates.

Do you clear " Allow Historical Dates" check box while processing the MRP run?

The allow historical is clear for our MRP runs.

Hi Matt,

Are you running MRP on a schedule? Do you have Dynamic checked on schedule start date? See posts below for details.


Hi Nancy,

We are in our TEST environment currently so are running MRP manually when required. We discovered the post you listed previously so have been through the steps on dynamic dates checkbox. Still no joy.



just to be certain.
this pertains to a PO SUGGESTION DATE in the PAST

and what is the ACTUAL START DATE you are using on the PROCESS MRP?

also - SET the LOGGING level MRP and Scheduling and then review the LOG - it will tell everything about the calcualtion

Just running MRP now we get the following new PO Suggestions in the past (Screenshot taken 11th DEC just after MRP run):


We have set the defaults on MRP to be


Looks like the parts with dates in the past had the constrained checkbox unchecked for some reason. Checking and running MRP brought dates in line.

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i see the date of Jan27 with 30 days lead time - which gives it more than enough time to order. i would be interested in seeing what the MRP LOG shows for this part. that will tell us what it was thinking

Hi @Matt_Belshaw,
has this issue been sorted ? if not i wonder if these boxes in Company Configuration have any effect in PO scheduling when operation or/and jobs are linked to purchased material part

We were able to discover the issue for the historical dates in that the checkbox for constrained had been unchecked without our knowledge. Reviewing the dates all made sense as the lead time was being followed but this meant for those parts and the job date the date was in the past. Now the issue is fixed the job has been moved and no dates are in the past. With this issue and a recent issue on scheduling it does seem to highlight a few gaps in the logic used to program the scheduling engine:

  • We are using constrained materials which I believe means we are in the minority of customers
  1. Having both boxes for allow scheduling before today/historical dates, Company Config & MRP respectively, seems to be just focused on the top level i.e. when you say when you want the job. Any calculations under that e.g. what’s the lead time for that part so when can I get it fall outside of the above restriction.
  2. Backward to forward scheduling - When Epcior can’t make a date for a job it switches from backward scheduling to forward scheduling. For us, having the jobs backward scheduling allows the scheduling board to look more like the actual scheduling and ordering of materials follows what we need it to. When forward scheduling it changes the look of the job and brings forward order dates of materials. Just an annoyance in the real world but it seems odd that you have to try to set a date for the job, without truly knowing when it will complete due to material availability of the thousands of parts we require, and if it can’t make that date it changes to forward scheduling so in essence Epicor does know how long the job takes at some point but doesn’t provide that info when entering the requested date. Some sort of prompt saying “I can’t make that date as some parts need another two weeks to arrive, do you want to move the job out or cancel?”

Hi Al,

Currently the issue is resolved but when our testing schedule permits I will try to run MRP with logging enabled.



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Looks like I wont be getting an opportunity to review this as we’ve made a decision to move away from constrained material which I have a hunch was causing the historical dates. Hate to leave a problem unsolved but there you go.

no sweat. i’ll keep it in mind.
ill be working on some site installs next year - we might run across it.
if so - i’ll loop back here
happy holidays