Error codes · EBA technical checks (reception)
306: XBRL instance documents must use UTF-8 encoding.
Rejects the file also shown as EBA.306
Official text
XBRL instance documents must use UTF-8 encoding.
How it appears in feedback
[table filename],,,306, XBRL instance documents must use UTF-8 encoding
What triggers it
A CSV or JSON file in the package is not UTF-8 (typically ANSI/Windows-1252 saved by Excel). Since 1 May 2025 this is a blocking reception check, because non-UTF-8 text was corrupting integrated data. A non-UTF-8 file also tends to cascade into 807/809 errors.
A file in the package is not valid UTF-8. Typically a CSV saved by Excel as “CSV (comma delimited)” on Windows, which uses the local code page, so names with é, ö or ß break.
Templates: all table files, report.json, parameters.csv, FilingIndicators.csv
How to fix it
Save every file as UTF-8. The EBA slides say UTF-8-BOM is also accepted at the ESAs, but the Central Bank of Ireland guide reports b_01.03.csv in UTF-8-BOM 'will cause errors' on its portal and tells filers to check 'UTF-8 and not UTF-8-BOM'; emit UTF-8 without BOM to be safe everywhere.
Save as “CSV UTF-8 (comma delimited)” in Excel, or convert with a text editor. A UTF-8 byte-order mark is accepted by the ESAs. Since 1 May 2025 this check rejects the whole file.
Conflict recorded verbatim: EBA observations slide 30: 'We will also accept UTF-8-BOM files as this is mandated by EBA filing rules'; CBI guide rule 306 example: 'The table file b_01.03.csv has been encoded in UTF-8-BOM format and this will cause errors in the validation of the file'.
Sources
- EBA, Overview of technical checks, validation rules and business checks to be applied by the EBA for RoI reporting (updated 28 April 2025), xlsx (read 2026-10-31)
- ESAs/EBA, Observations from reporting of RoI to the ESAs - key common issues identified (16 Apr 2025, updated 16 May 2025), slides (read 2026-10-31)
- CSSF, Guidance for interpretation and resolution of ESA error messages related to the DORA register, v1.0, 15 May 2025 (read 2026-10-31)
- Central Bank of Ireland, Guide to Submitting DORA Registers of Information on the Central Bank of Ireland Portal (PDF dated 23 Feb 2026, 93 pp.) (read 2026-10-31)