In a recent implementation of Dynamics NAV 2018, the client has requested to upload the master data from their old legacy ERP system.

In the old ERP system, there was two unit of measurements which are:

[icon name=”adjust” class=”” unprefixed_class=””] Each

[icon name=”adjust” class=”” unprefixed_class=””] Piece

Now logically speaking, both are just an identifier of one unit, regardless of the terminology used to describe this unit. Import occurred at the beginning of the year, and then opening balances and transactions have been posted to all the items throughout the whole year. Now, at the year-end closing, the client decided to clean their data after reaching a stability status, and for that purpose, they decided to link all items to the unit of measurement “Each”, rather than “Piece”. Therefore, the result should be one unit of measurements “EA”, and the piece should be cleared from the system.

In Dynamics NAV, when you change the unit of measurement for an item with existing open ledger entries, an error message would pop up as illustrated below:

Dynamics NAV - Change Item Base Unit of Measurement

Change Base Unit of Measurement Error

The error indicates the following:

” You cannot change base unit of measure because there are one or more open ledger entries for this item ( select refresh to discard errors ) “

When looking at the ledger entries of the item, you will find that there is an open balance for this item as illustrated below:

Dynamics NAV - Change Item Base Unit of Measurement
Item Balance


In order to be able to change the unit of measurement, the item balance should be zero. Which means, that there should be no open ledger entries at all.

  1. Create an item journal, entry type is a negative adjustment which results with zero inventory balance.
  2. Change the base unit of measure of the item.
  3. Create an item journal, entry type is a positive adjustment with the exact same balance which was adjusted out


Important Note:

After changing the base unit of measurement of the item, the system keeps a record in the item unit of measurement table that the item has two unit of measures, the old one and the new one. Here is an item which has been changed from Piece to Each.

Dynamics NAV - Change Item Base Unit of Measurement
Item Unit of Measure

It is not recommended to delete the old unit of measure from the item unit of measure table due to having historical transactions. Such deletion would occur with relational errors as the one stated below for an item used in production BOM, which has been linked with Each and then changed to Piece, and then “Each” was deleted from the item unit of measure table.

Error Message

“The field unit of measure code of the table prod. order component contains a value (Each) that cannot be found in the related table ( Item Unit of Measure) “

Dynamics NAV - Change Item Base Unit of Measurement