✅ 1. Confirm the Sheet and Header Names Match Exactly
Open your Data Importer Document in Mendix Studio Pro → check:
The sheet name is identical (case-sensitive) to the sheet name in Excel.
The column headers in Excel exactly match the field names in the Import Mapping.
Even small differences (extra spaces, capitalization, hidden characters) cause a silent skip.
💡 Tip: Try opening Excel, retyping header names, and saving as .xlsx
(not .xls
).
✅ 2. Check That the FileDocument Is Passed Correctly
If you’re running the import via microflow, make sure:
The input parameter to your “Import with Mapping” action is your uploaded FileDocument, not a system-level document.
In the Import Call:
Source Type: Data Importer Document
File parameter: $YourUploadedFile
✅ 3. Validate the Import Mapping Structure
Open the Import Mapping → ensure it’s using the Data Importer Document as source, not XML/JSON.
Check the mapping mode:
If you use “Find by key” and no key matches, objects won’t be created.
For testing, set “Create new objects” to confirm the mapping works.
💡 Debug step: Temporarily map only one simple column → one simple attribute (like “Name”).If that works, the issue is deeper in your mapping structure.
✅ 4. Turn On Mendix Logging
Go to Console → Set Log Levels:
Set DataImporter
and ImportMapping
to Trace level.Then re-run your import and check the console output.
You’ll see messages like:
DataImporter: Reading sheet 'Sheet1' with 25 rows ImportMapping: Mapping row 2 to entity MyModule.Customer
If you don’t see “Mapping row…”, it means no rows were parsed (likely header mismatch or wrong sheet).
✅ 5. Check for Empty Cells or Hidden Rows
If your Excel file has:
Merged cells,
Hidden header row,
Empty first row (above headers),
Mendix will treat it as invalid input and skip parsing.
💡 Fix: Clean up the Excel file → header row must be the first row of actual data.
✅ 6. Verify the Microflow Flow
A typical working flow looks like this:
Start ↓ Upload (FileDocument) ↓ Call Import Mapping (Source: Data Importer Document) - FileDocument: $UploadedFile - Mapping: YourMapping ↓ Commit or Display Result
If you added a custom “Create Object” microflow, confirm:
It’s actually referenced in your Import Mapping (“Create object with microflow” option).
It returns the correct object type (same as mapped entity).
If it’s never called → mapping is never triggered.
✅ 7. Test with “Upload → Save → Manually Run Import”
To isolate the issue:
Upload the file.
Save it to your local file storage.
Open your Data Importer Document in Studio Pro → select “Run locally” with the same file.If it imports there, your issue is in the runtime microflow (not mapping or data).