Common Issues

Data issues

Special characters appear garbled when opening the file in Excel

If accented characters, currency symbols, or non-Latin text appear as garbled characters when you open the downloaded file in Microsoft Excel, the Excel-friendly mode (BOM) may be turned off.

Fix: Open your data flow's destination settings and make sure Excel-friendly mode is enabled. This adds a byte order mark (BOM) to the file, which tells Excel to interpret the file as UTF-8. Re-run the data flow and download the file again.

This setting is enabled by default. If you previously disabled it and are opening the file in Excel, turn it back on.

Column headers are missing from the downloaded file

If your file starts directly with data rows and has no header row, the Include headers setting may be turned off.

Fix: Open your data flow's destination settings and make sure Include headers is enabled. Re-run the data flow and download the file again. The first row will contain column names.

Numbers or dates are formatted incorrectly in Excel

Excel applies its own formatting rules when opening files. Numbers may appear as text, dates may display in an unexpected format, or leading zeros may be stripped from values like ZIP codes or product codes.

Fix: After opening the file, select the affected column, right-click, choose Format Cells, and set the appropriate number or date format. For values that need leading zeros preserved (such as ZIP codes), format the column as Text before pasting or importing the data.

Large files are slow to open or cause Excel to freeze

If your data flow exports a very large number of rows, the downloaded file may take a long time to open or cause Excel to become unresponsive.

Fix: Reduce the amount of data exported by applying filters or limiting the date range in your source configuration. If you regularly work with large datasets (hundreds of thousands of rows), consider using a database destination like BigQuery or PostgreSQL instead.

Excel supports a maximum of 1,048,576 rows per sheet. If your export exceeds this limit, some data will be truncated when opened in Excel.

Download issues

No file available for download after the data flow run

If you don't see a download option after the data flow finishes, the run may not have completed successfully.

Fix: Check the data flow run history in Coupler.io. If the run shows an error, fix the source configuration and re-run the flow. The download is only available after a successful run.

The downloaded file is empty

If the file downloads but contains no data (or only headers), the source query may have returned zero rows.

Fix: Verify that the source configuration is correct — check filters, date ranges, and access permissions on the source side. Preview the data in Coupler.io before running the flow to confirm rows are being returned.