web
You’re offline. This is a read only version of the page.
close
Skip to main content

Notifications

Announcements

No record found.

News and Announcements icon
Community site session details

Community site session details

Session Id :
Dynamics 365 Community / Forums / Small and medium business | Business Central, N... / how to troubleshoot: M...
Small and medium business | Business Central, N...
Suggested Answer

how to troubleshoot: MRP/MPS: "Error when calculating backward. Calendar is not available before 01.01.1980 for Machine Center xy"

(0) ShareShare
ReportReport
Posted on by benovic 350

i have a case where i geht this error message in production, when running MRP/MPS.

 "Error when calculating backward. Calendar is not available before 01.01.1980 for Machine Center xy"

we extended the calendar until 1980 to check, but it seems even this is not enough.

I re-checked all the machine center lead times, checked on th earticle card, in the ressource calendars and found nothing that would indicate why the MPS is planning 40 Years backwards for our orders.

IN order to find the error, it would be nice to be able to get more insight.

any tips on how i could see what lines create the very long backwards planning?

I have the same question (0)
  • Suggested answer
    MahGah Profile Picture
    MahGah 15,529 on at

    Hi

    For machine center xy what is the UOM, Capacity , and Efficiency? Also, can you see a big production order?

    My guess is you have one big production order and when system uses the machine center / calendar setup and goes backward to set the start date it needs to go way back to calculate correct start date.

    Let say you want to make 1000 of one item and your capacity for machine center set to month and then uses 6 months then system needs to go back 500 years as a staring point.

    But I could be wrong here as well.

    I hope Ben Baxter  can provide a better explanation. 

  • Suggested answer
    Ben Baxter Profile Picture
    Ben Baxter 6,620 Super User 2025 Season 2 on at

    MahGah is spot on.  When creating/refreshing the Production Order the system is trying to calculate the start date.  This means it is taking the quantity times the run time of the routing lines to calculate the start time of each routing step.  The issue might not be Machine Center xy, but rather another operation happening prior that is pushing xy to start in the past.

    Check your Capacity Units of Measure on your Run Times for the Routing, which could be different than the machine card.  Then look at the calendar capacity for your machines.  Make sure the machines have availability to complete the operation(s) within a reasonable timeframe.

    This is most likely a mistaken Routing entry, such as 1000 minutes instead of .1000 minutes, which makes a huge difference in capacity requirements.

    Let us know what you find.

    Best Regards,

    Ben Baxter

Under review

Thank you for your reply! To ensure a great experience for everyone, your content is awaiting approval by our Community Managers. Please check back later.

Helpful resources

Quick Links

Responsible AI policies

As AI tools become more common, we’re introducing a Responsible AI Use…

Neeraj Kumar – Community Spotlight

We are honored to recognize Neeraj Kumar as our Community Spotlight honoree for…

Congratulations to the November Top 10 Community Leaders!

These are the community rock stars!

Leaderboard > Small and medium business | Business Central, NAV, RMS

#1
OussamaSabbouh Profile Picture

OussamaSabbouh 2,238

#2
YUN ZHU Profile Picture

YUN ZHU 773 Super User 2025 Season 2

#3
Sumit Singh Profile Picture

Sumit Singh 630

Last 30 days Overall leaderboard

Featured topics

Product updates

Dynamics 365 release plans