diff --git a/app/models/dmsf_file.rb b/app/models/dmsf_file.rb
index 38c39748..28ff9a8b 100644
--- a/app/models/dmsf_file.rb
+++ b/app/models/dmsf_file.rb
@@ -524,7 +524,7 @@ class DmsfFile < ActiveRecord::Base
       RedmineDmsf::Preview.generate last_revision&.disk_file.to_s, target
     rescue => e
       Rails.logger.error "An error occurred while generating preview for #{last_revision&.disk_file} to #{target}\nException was: #{e.message}"
-      nil
+      ''
     end
   end