diff --git a/fastlane_core/lib/fastlane_core/pkg_upload_package_builder.rb b/fastlane_core/lib/fastlane_core/pkg_upload_package_builder.rb
index c96b864ed2d..b208cdd3df4 100644
--- a/fastlane_core/lib/fastlane_core/pkg_upload_package_builder.rb
+++ b/fastlane_core/lib/fastlane_core/pkg_upload_package_builder.rb
@@ -22,7 +22,7 @@ def generate(app_id: nil, pkg_path: nil, package_path: nil, platform: "osx")
         apple_id: app_id,
         file_size: File.size(pkg_path),
         ipa_path: File.basename(pkg_path), # this is only the base name as the ipa is inside the package
-        md5: Digest::MD5.hexdigest(File.read(pkg_path)),
+        md5: calculate_md5(pkg_path),
         archive_type: 'product-archive',
         platform: platform
       }
@@ -41,9 +41,33 @@ def generate(app_id: nil, pkg_path: nil, package_path: nil, platform: "osx")
     def copy_pkg(pkg_path)
       ipa_file_name = Digest::MD5.hexdigest(pkg_path)
       resulting_path = File.join(self.package_path, "#{ipa_file_name}.pkg")
-      FileUtils.cp(pkg_path, resulting_path)
 
-      resulting_path
+      begin
+        File.open(pkg_path, 'rb') do |src|
+          File.open(resulting_path, 'wb') do |dst|
+            while (buffer = src.read(1024 * 1024)) do
+              dst.write(buffer)
+            end
+          end
+        end
+        return resulting_path
+      rescue StandardError => e
+        UI.user_error!("Error copying file '#{pkg_path}' to '#{resulting_path}': #{e.message}")
+      end
+    end
+
+    def calculate_md5(file_path)
+      begin
+        md5 = Digest::MD5.new
+        File.open(file_path, 'rb') do |file|
+          while (buffer = file.read(1024 * 1024)) do
+            md5.update(buffer)
+          end
+        end
+        return md5.hexdigest
+      rescue StandardError => e
+        UI.user_error!("Error reading file '#{file_path}': #{e.message}")
+      end
     end
   end
 end