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What does “Gen. Posting Type must not be” mean?

One of the most common issues our clients run into across all versions of NAV and Business Central is this error message when posting journals.

The resolution is not as simple as changing the Gen. Posting Type field. Before knowing how to fix it it’s important to understand why the error is occurring so you can fix it in the correct way and stop it happening again. Usually this error occurs when: either Posting Groups are populated without a Gen Posting Type or vice versa, so you must understand these fields and how they are populated in the Journal.

General Posting Type

Firstly the “General Posting Type” field. This field is attached to any transaction impacting the General Ledger and is primarily used in GST Reporting (i.e. BAS Statement). There are 4 options:

  1. Blank. This is when the transaction is not a GST related transaction, most commonly used on financial journals such as accruals or distribution of costs between divisions
  2. Purchase. This will impact the GST Paid/Purchases area of the BAS
  3. Sale. This will impact GST Collected/Sales area of the BAS
  4. Settlement. Reserved for posting GST Settlements

To determine the correct value for Gen. Posting Type, decide whether the transaction you are doing should have an impact on your BAS or not. If the answer is no, then the Gen. Posting Type must remain blank. If the answer is yes, you will need a Gen. Posting Type of either Purchase or Sale.

Posting Groups

The next decision is the Posting Groups. If you have selected Gen. Posting Type of Purchase or Sale, you will need Posting Groups (General Business, GST Business, General Product & GST Product) to be populated in order to calculate the GST Values and post them correctly to the General and GST Ledgers. If the Gen. Posting Type is blank, all the posting groups must be blank as no GST should be calculated.

Correct Setup of G/L Accounts

The “Posting” tab NAV G/L Account Card has fields on it used to default these values on General Journal Lines

The “Posting” tab NAV G/L Account Card

There are some simple rules to follow for each G/L Account:

  1. If the G/L Account is a Control Account for a Subledger (e.g. Accounts Receivable) they should all be blank
  2. If the G/L Account is to be posted to through documents (Purchase or Sale Order, Invoice or Cr/Adj Note) you will need a “Gen. Product Posting Group” and a “GST Prod. Posting Group”
  3. If the G/L Account it to be posted to through a Journal, and GST should be calculated (e.g. Bank Fees which are inclusive of GST) you will need to populate “Gen. Posting Type”, “Gen. Bus. Posting Group”, “GST Bus. Posting Group”, “Gen. Prod. Posting Group” and “GST Product Posting Group”
  4. If the posting to the G/L Account is only through Journals, and these journals should have no GST or BAS impact (e.g. an end of month adjustment account) then all fields should be blank

Setup of Journal Templates and Batches

When the G/L Account is selected on the Journal Line, NAV will only populate the Gen. Posting Type and Posting Groups if the “Copy GST Setup to Jnl Lines” is ticked on the Journal Batch you are in. This in turn defaults from the Journal Template you are using. Therefore we recommend reviewing the Journal Templates (Departments/Financial Management/Setup/General/General Journal Templates) for each one:

  • If the Journal Template will usually have transactions with GST (e.g. Purchase Journals or Sales Journals) it should be ticked
  • If the Journal Template will usually have transactions with no GST impact (e.g. General Journals, Recurring Journals, Payments & Receipts) it should not be ticked
General Journal Templates

If there are exceptions to this (e.g. there is one batch of Cash Receipts where you handle rebates which include GST) it should be selected on that particular batch

Cash Receipt Journals


Now you understand where the message comes from, you should know to follow these steps:

  1. To get the journal to post, either clear out Posting Setup and Posting Groups or ensure all are populated; Review the G/L Accounts, General Journal Template, and General Journal batch in question and ensure they are setup correctly
  2. Review the G/L Accounts, General Journal Template, and General Journal batch in question and ensure they are setup correctly