diff --git a/CHANGELOG b/CHANGELOG
index c4586485c..ebc7e854c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -33,6 +33,7 @@ CHANGELOG Roundcube Webmail
 - Fix bug where new messages weren't added to the list in search mode
 - Fix wrong positioning of message list header on page scroll in Webkit browsers (#1490035)
 - Fix some javascript errors in rare situations (#1490441)
+- Fix error when using back button after sending an email (#1490009)
 
 RELEASE 1.1.2
 -------------
diff --git a/index.php b/index.php
index 5cfd8df10..c029b5a26 100644
--- a/index.php
+++ b/index.php
@@ -131,7 +131,7 @@ if ($RCMAIL->task == 'login' && $RCMAIL->action == 'login') {
 
             // prevent redirect to compose with specified ID (#1488226)
             if ($query['_action'] == 'compose' && !empty($query['_id'])) {
-                $query = array();
+                $query = array('_action' => 'compose');
             }
         }
 
diff --git a/program/localization/en_US/messages.inc b/program/localization/en_US/messages.inc
index a23bfd645..621b7eafd 100644
--- a/program/localization/en_US/messages.inc
+++ b/program/localization/en_US/messages.inc
@@ -189,5 +189,6 @@ $messages['errrequestcheckfailed'] = 'Request Check Failed';
 $messages['errcsrfprotectionexplain'] = "For your protection, access to this resource is secured against CSRF.\nIf you see this, you probably didn't log out before leaving the web application.\n\nHuman interaction is now required to continue.";
 $messages['errcontactserveradmin'] = 'Please contact your server-administrator.';
 $messages['clicktoresumesession'] = 'Click here to resume your previous session';
-
-?>
+$messages['errcomposesession'] = 'Compose session error';
+$messages['errcomposesessionexplain'] = 'Requested compose session not found.';
+$messages['clicktocompose'] = 'Click here to compose a new message';
diff --git a/program/steps/mail/compose.inc b/program/steps/mail/compose.inc
index 8fffbd4de..84ec3c32a 100644
--- a/program/steps/mail/compose.inc
+++ b/program/steps/mail/compose.inc
@@ -47,9 +47,11 @@ while ($COMPOSE_ID && !is_array($COMPOSE) && $RCMAIL->db->is_replicated() && $re
 if (!is_array($COMPOSE)) {
     // Infinite redirect prevention in case of broken session (#1487028)
     if ($COMPOSE_ID) {
-        rcube::raise_error(array('code' => 500, 'type' => 'php',
-            'file' => __FILE__, 'line' => __LINE__,
-            'message' => "Invalid compose ID"), true, true);
+        // if we know the message with specified ID was already sent
+        // we can ignore the error and compose a new message (#1490009)
+        if ($COMPOSE_ID != $_SESSION['last_compose_session']) {
+            rcube::raise_error(array('code' => 450), false, true);
+        }
     }
 
     $COMPOSE_ID = uniqid(mt_rand());
diff --git a/program/steps/mail/func.inc b/program/steps/mail/func.inc
index 9a734329f..6e2f982db 100644
--- a/program/steps/mail/func.inc
+++ b/program/steps/mail/func.inc
@@ -1753,20 +1753,6 @@ function rcmail_draftinfo_decode($str)
     return $info;
 }
 
-/**
- * clear message composing settings
- */
-function rcmail_compose_cleanup($id)
-{
-    if (!isset($_SESSION['compose_data_'.$id])) {
-        return;
-    }
-
-    $rcmail = rcmail::get_instance();
-    $rcmail->plugins->exec_hook('attachments_cleanup', array('group' => $id));
-    $rcmail->session->remove('compose_data_'.$id);
-}
-
 /**
  * Send the MDN response
  *
diff --git a/program/steps/mail/sendmail.inc b/program/steps/mail/sendmail.inc
index bb1b6029a..d83f26e6a 100644
--- a/program/steps/mail/sendmail.inc
+++ b/program/steps/mail/sendmail.inc
@@ -958,3 +958,19 @@ function rcmail_generic_message_footer($isHtml)
 
     return false;
 }
+
+/**
+ * clear message composing settings
+ */
+function rcmail_compose_cleanup($id)
+{
+    if (!isset($_SESSION['compose_data_'.$id])) {
+        return;
+    }
+
+    $rcmail = rcmail::get_instance();
+    $rcmail->plugins->exec_hook('attachments_cleanup', array('group' => $id));
+    $rcmail->session->remove('compose_data_'.$id);
+
+    $_SESSION['last_compose_session'] = $id;
+}
diff --git a/program/steps/utils/error.inc b/program/steps/utils/error.inc
index 3b1d926b6..7ca933e52 100644
--- a/program/steps/utils/error.inc
+++ b/program/steps/utils/error.inc
@@ -72,6 +72,15 @@ else if ($ERROR_CODE == 404) {
     $__error_text .= '<p><i>' . $rcmail->gettext('errfailedrequest') . ":</i><br />\n<tt>//$request_url</tt></p>";
 }
 
+// invalid compose ID
+else if ($ERROR_CODE == 450 && $_SERVER['REQUEST_METHOD'] == 'GET' && $rcmail->action == 'compose') {
+    $url = $rcmail->url('compose');
+
+    $__error_title = strtoupper($rcmail->gettext('errcomposesession'));
+    $__error_text  = nl2br($rcmail->gettext('errcomposesessionexplain'))
+        . '<p>' . html::a($url, $rcmail->gettext('clicktocompose')) . '</p>';
+}
+
 // database connection error
 else if ($ERROR_CODE == 601) {
     $__error_title = "CONFIGURATION ERROR";