Problem
Customers report that receipts posted in DATEV do not contain the pre‑accounting details they entered in Moss (e.g. accounts, cost centers, tax keys), or that transactions are not posted against the expected Moss Wallet account. In many cases, this worked correctly in the past.
This article explains how to troubleshoot the issue step by step and identify whether the change happened before or after the data left Moss.
How Moss → DATEV posting works (short overview)
Moss sends all receipt data and pre‑accounting information to DATEV Unternehmen online (DUO). From there, DATEV Rechnungswesen applies its own automations (for example Lerndatei rules or manual edits).
👉 Moss can only control the data up to DUO. Any changes applied afterwards in DATEV are outside of Moss’ control.
Step 1: Check what Moss actually sent to DATEV
Before changing any settings in DATEV, verify whether Moss exported the correct data.
How to check
Open DATEV Rechnungswesen.
Open the posting in question.
Open the attached digital receipt.
Scroll to the last page of the document.
DATEV automatically adds a protocol page to the receipt. This protocol lists the data that were sent from Moss, for example:
Account
Cost center(s)
Tax key
Business partner / wallet reference
Interpretation
Protocol data = correct, posting = wrong
→ The data were changed after the Moss export (manual change or DATEV automation).Protocol data already incorrect
→ Please contact Moss Support and include the receipt and transaction details.
Step 2: Check the DATEV “Lerndatei” (most common cause)
The most frequent reason for overwritten pre‑accounting is an active Lerndatei in DATEV. The Lerndatei automatically replaces posting data based on past behavior and can override Moss imports without warning.
How to check the Lerndatei
Open DATEV Rechnungswesen.
Go to Stammdaten.
Select Lerndatei.
Open Rechnungseingang.
You will see a list of learned rules (e.g. accounts, cost centers, tax keys).
What to do
Recommended: Delete all entries to prevent overrides of Moss data.
If you need Lerndatei rules for other workflows:
Review them carefully.
Make sure they do not conflict with Moss pre‑accounting (accounts, KOST1/KOST2, tax logic, wallet accounts).
⚠️ Even a single Lerndatei entry can silently overwrite all Moss values.
Step 3: Check for other DATEV automations or manual changes
Besides the Lerndatei, the following can also change postings:
Manual edits in DATEV Unternehmen online
Manual edits in DATEV Rechnungswesen
Other DATEV automation rules
If the protocol page shows correct Moss data, any of the above occurred after the Moss export.
Important limitations to be aware of
Moss controls data until they are transferred to DATEV DUO.
Moss cannot detect or prevent:
Lerndatei overrides
Manual changes in DATEV
Other DATEV automations applied after import
Summary
Check | Result | Conclusion |
Protocol page | Data correct | Change happened in DATEV |
Protocol page | Data wrong | Issue before or during Moss export |
Lerndatei active | Entries present | Moss data likely overridden |
In most cases, disabling or cleaning the Lerndatei (Rechnungseingang) resolves the issue permanently.