diff --git a/src/Spout/Reader/XLSX/Helper/StyleHelper.php b/src/Spout/Reader/XLSX/Helper/StyleHelper.php
index 403d647..5732948 100644
--- a/src/Spout/Reader/XLSX/Helper/StyleHelper.php
+++ b/src/Spout/Reader/XLSX/Helper/StyleHelper.php
@@ -201,6 +201,10 @@ class StyleHelper
 
         $customNumberFormat = $customNumberFormats[$numFmtId];
 
+        if ($customNumberFormat === 'General') {
+            return false;
+        }
+
         // Remove extra formatting (what's between [ ], the brackets should not be preceded by a "\")
         $pattern = '((?<!\\\)\[.+?(?<!\\\)\])';
         $customNumberFormat = preg_replace($pattern, '', $customNumberFormat);
diff --git a/tests/Spout/Reader/XLSX/Helper/StyleHelperTest.php b/tests/Spout/Reader/XLSX/Helper/StyleHelperTest.php
index 3b8edff..0266776 100644
--- a/tests/Spout/Reader/XLSX/Helper/StyleHelperTest.php
+++ b/tests/Spout/Reader/XLSX/Helper/StyleHelperTest.php
@@ -111,6 +111,7 @@ class StyleHelperTest extends \PHPUnit_Framework_TestCase
             ['m/d/yyyy;@', true],
             ['[$-409]m/d/yy\--h:mm;@', true],
             ['GENERAL', false],
+            ['General', false],
             ['\ma\yb\e', false],
             ['[Red]foo;', false],
         ];