diff --git a/src/Composer/Command/InstallCommand.php b/src/Composer/Command/InstallCommand.php
index a163d5ad5..955607c85 100644
--- a/src/Composer/Command/InstallCommand.php
+++ b/src/Composer/Command/InstallCommand.php
@@ -76,7 +76,10 @@ EOT
 
         $preferSource = false;
         $preferDist = false;
-        switch ($composer->getConfig()->get('preferred-install')) {
+
+        $config = $composer->getConfig();
+
+        switch ($config->get('preferred-install')) {
             case 'source':
                 $preferSource = true;
                 break;
@@ -93,6 +96,8 @@ EOT
             $preferDist = $input->getOption('prefer-dist');
         }
 
+        $optimize = $input->getOption('optimize-autoloader') || $config->get('optimize-autoloader');
+
         $install
             ->setDryRun($input->getOption('dry-run'))
             ->setVerbose($input->getOption('verbose'))
@@ -100,7 +105,7 @@ EOT
             ->setPreferDist($preferDist)
             ->setDevMode(!$input->getOption('no-dev'))
             ->setRunScripts(!$input->getOption('no-scripts'))
-            ->setOptimizeAutoloader($input->getOption('optimize-autoloader'))
+            ->setOptimizeAutoloader($optimize)
         ;
 
         if ($input->getOption('no-plugins')) {
diff --git a/src/Composer/Command/UpdateCommand.php b/src/Composer/Command/UpdateCommand.php
index 7a1471a65..c3c90b94d 100644
--- a/src/Composer/Command/UpdateCommand.php
+++ b/src/Composer/Command/UpdateCommand.php
@@ -81,7 +81,10 @@ EOT
 
         $preferSource = false;
         $preferDist = false;
-        switch ($composer->getConfig()->get('preferred-install')) {
+
+        $config = $composer->getConfig();
+
+        switch ($config->get('preferred-install')) {
             case 'source':
                 $preferSource = true;
                 break;
@@ -98,6 +101,8 @@ EOT
             $preferDist = $input->getOption('prefer-dist');
         }
 
+        $optimize = $input->getOption('optimize-autoloader') || $config->get('optimize-autoloader');
+
         $install
             ->setDryRun($input->getOption('dry-run'))
             ->setVerbose($input->getOption('verbose'))
@@ -105,7 +110,7 @@ EOT
             ->setPreferDist($preferDist)
             ->setDevMode(!$input->getOption('no-dev'))
             ->setRunScripts(!$input->getOption('no-scripts'))
-            ->setOptimizeAutoloader($input->getOption('optimize-autoloader'))
+            ->setOptimizeAutoloader($optimize)
             ->setUpdate(true)
             ->setUpdateWhitelist($input->getOption('lock') ? array('lock') : $input->getArgument('packages'))
             ->setWhitelistDependencies($input->getOption('with-dependencies'))
diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index 900c14b6b..e1dbd496f 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -279,7 +279,12 @@ class Installer
             }
 
             // write autoloader
-            $this->io->write('<info>Generating autoload files</info>');
+            if ($this->optimizeAutoloader) {
+                $this->io->write('<info>Generating optimized autoload files</info>');
+            } else {
+                $this->io->write('<info>Generating autoload files</info>');
+            }
+
             $this->autoloadGenerator->dump($this->config, $localRepo, $this->package, $this->installationManager, 'composer', $this->optimizeAutoloader);
 
             if ($this->runScripts) {