diff --git a/app/helpers/dmsf_upload_helper.rb b/app/helpers/dmsf_upload_helper.rb
index afb01005..94f359ce 100644
--- a/app/helpers/dmsf_upload_helper.rb
+++ b/app/helpers/dmsf_upload_helper.rb
@@ -94,7 +94,7 @@ module DmsfUploadHelper
             new_revision.file.attach(
               io: File.open(committed_file[:tempfile_path]),
               filename: new_revision.name,
-              content_type: new_revision.content_type,
+              content_type: committed_file[:mime_type],
               identify: false
             )
             file.last_revision = new_revision
diff --git a/app/models/dmsf_file_revision.rb b/app/models/dmsf_file_revision.rb
index b07048e5..369ec994 100644
--- a/app/models/dmsf_file_revision.rb
+++ b/app/models/dmsf_file_revision.rb
@@ -278,12 +278,7 @@ class DmsfFileRevision < ApplicationRecord
   end
 
   def copy_file_content(open_file)
-    file.attach(
-      io: open_file,
-      filename: dmsf_file.name,
-      content_type: content_type,
-      identify: false
-    )
+    file.attach io: open_file, filename: dmsf_file.name
   end
 
   # Overrides Redmine::Acts::Customizable::InstanceMethods#available_custom_fields