diff --git a/ckanext/odsh/validation.py b/ckanext/odsh/validation.py
index 9cbb39eabea86c8e3421cb86c98a8d87e3667eb4..9858858935d543834958b505edae5215c9669735 100644
--- a/ckanext/odsh/validation.py
+++ b/ckanext/odsh/validation.py
@@ -359,6 +359,9 @@ def validate_relatedPackage(data):
             raise toolkit.Invalid("relatedPackage: package '{}' not found".format(data))
 
 def validate_formats(data, errors):
+    if not data:
+        raise toolkit.Invalid('Missing format.')
+
     if not data.upper() in ['7Z','AAB','AAC','AKN4EU','AKN4EU_ZIP','APK','APPX','ARC','ARC_GZ','ARCINFO_COV','ARJ','ATOM','AZW','BIN','BITS','BMP','BWF','BZIP2','CSS','CSV','DBF','DCR','DEB','DGN','DMG','DMP','DOC','DOCX','DTD_SGML','DTD_XML','DWG','DXF','E00','EAR','ECW','EPS','EPUB','ETSI_XML','EXE','FMX2','FMX3','FMX4','FMX4_ZIP','GDB','GEOJSON','GEOTIFF','GIF','GML','GMZ','GPKG','GRID','GRID_ASCII','GZIP','HDF','HDT','HTML','HTML5','HTML_SIMPL','ICS','IMMC_XML','INDD','IPA','ISO','ISO_ZIP','JAR','JATS','JPEG','JPEG2000','JS','JSON','JSON_LD','KML','KMZ','LAS','LAZ','LEG','LHA','LPK','LZIP','LZMA','LZO','MAP_PRVW','MAP_SRVC','MBOX','MDB','METS','METS_ZIP','MHTML','MIF_MID','MOBI','MOP','MPEG2','MPEG4','MPEG4_AVC','MRSID','MSG_HTTP','MSI','MXD','N3','NETCDF','OCTET','ODB','ODC','ODF','ODG','ODP','ODS','ODT','OP_DATPRO','OVF','OWL','PDF','PDF1X','PDFA1A','PDFA1B','PDFA2A','PDFA2B','PDFA3','PDFUA','PDFX','PDFX1A','PDFX2A','PDFX4','PL','PNG','PPS','PPSX','PPT','PPTX','PS','PSD','PWP','QGS','RAR','RDF','RDFA','RDF_N_QUADS','RDF_N_TRIPLES','RDF_TRIG','RDF_TRIX','RDF_TURTLE','RDF_XML','REST','RPM','RSS','RTF','SB3','SCHEMA_XML','SDMX','SGML','SHP','SKOS_XML','SPARQLQ','SPARQLQRES','SQL','STL','SVG','SWM','TAB','TAB_RSTR','TAR','TAR_GZ','TAR_XZ','TIFF','TIFF_FX','TMX','TSV','TXT','UNGEN','WAR','WARC','WARC_GZ','WCS_SRVC','WFS_SRVC','WIM','WMS_SRVC','WORLD','XHTML','XHTML_SIMPL','XLIFF','XLS','XLSB','XLSM','XLSX','XML','XSLFO','XSLT','XYZ','XZ','Z','ZIP']:
         raise toolkit.Invalid(_('Only formats on the list of the EU Publications Office are allowed.'))