diff --git a/pom.xml b/pom.xml
index 86b7cae..dc14d7a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <groupId>uk.ac.ebi.pride</groupId>
     <artifactId>px-submission-core</artifactId>
     <name>px-submission-core</name>
-    <version>2.0.35</version>
+    <version>2.0.36</version>
     
     <parent>
         <groupId>uk.ac.ebi.pride.architectural</groupId>
diff --git a/src/main/java/uk/ac/ebi/pride/data/validation/SubmissionValidator.java b/src/main/java/uk/ac/ebi/pride/data/validation/SubmissionValidator.java
index 8b455c7..575f250 100755
--- a/src/main/java/uk/ac/ebi/pride/data/validation/SubmissionValidator.java
+++ b/src/main/java/uk/ac/ebi/pride/data/validation/SubmissionValidator.java
@@ -792,9 +792,14 @@ private static void validateDataFile(DataFile dataFile, ValidationReport report)
                     report.addMessage(new ValidationMessage(ValidationMessage.Type.ERROR, "# is not allowed in the file name '" + actualFile.getName() + "'"));
                 }
 
-                if (!dataFile.getFileName().matches("[^-_.A-Za-z0-9]")){
-                    report.addMessage(new ValidationMessage(ValidationMessage.Type.WARNING, "POSIX compatible charset is NOT used in file name '" + actualFile.getName() + "'"));
+                if (dataFile.getFileName().matches("[^-_.A-Za-z0-9]")){
+                    report.addMessage(new ValidationMessage(ValidationMessage.Type.ERROR, "POSIX compatible charset is NOT used in file name '" + actualFile.getName() + "'"));
                 }
+
+                if (!dataFile.getFileName().matches("^[A-Za-z0-9].*")){
+                    report.addMessage(new ValidationMessage(ValidationMessage.Type.ERROR, "Filenames should start with alpha numeric characters '" + actualFile.getName() + "'"));
+                }
+
             } else if (!dataFile.isUrl()) {
                 // Accept URL
                 report.addMessage(new ValidationMessage(ValidationMessage.Type.ERROR, "Data file is not a file: " + dataFile.getFileId()));