diff --git a/lib/adminlib.php b/lib/adminlib.php
index 3df2cc3d6ad..7540be3f73c 100644
--- a/lib/adminlib.php
+++ b/lib/adminlib.php
@@ -2543,9 +2543,10 @@ class admin_setting_configexecutable extends admin_setting_configfile {
     public function output_html($data, $query='') {
         global $CFG;
         $default = $this->get_defaultsetting();
+        require_once("$CFG->libdir/filelib.php");
 
         if ($data) {
-            if (file_exists($data) and !is_dir($data) and is_executable($data)) {
+            if (file_exists($data) and !is_dir($data) and file_is_executable($data)) {
                 $executable = '<span class="pathok">&#x2714;</span>';
             } else {
                 $executable = '<span class="patherror">&#x2718;</span>';
diff --git a/lib/filelib.php b/lib/filelib.php
index 246aaad3cb1..c26865d54c8 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -2659,6 +2659,35 @@ function file_modify_html_header($text) {
     return $text;
 }
 
+/**
+ * Tells whether the filename is executable.
+ *
+ * @link http://php.net/manual/en/function.is-executable.php
+ * @link https://bugs.php.net/bug.php?id=41062
+ * @param string $filename Path to the file.
+ * @return bool True if the filename exists and is executable; otherwise, false.
+ */
+function file_is_executable($filename) {
+    if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
+        if (is_executable($filename)) {
+            return true;
+        } else {
+            $fileext = strrchr($filename, '.');
+            // If we have an extension we can check if it is listed as executable.
+            if ($fileext && file_exists($filename) && !is_dir($filename)) {
+                $winpathext = strtolower(getenv('PATHEXT'));
+                $winpathexts = explode(';', $winpathext);
+
+                return in_array(strtolower($fileext), $winpathexts);
+            }
+
+            return false;
+        }
+    } else {
+        return is_executable($filename);
+    }
+}
+
 /**
  * RESTful cURL class
  *
diff --git a/lib/filestorage/file_storage.php b/lib/filestorage/file_storage.php
index 6ccb84e93d7..e4b1dde181f 100644
--- a/lib/filestorage/file_storage.php
+++ b/lib/filestorage/file_storage.php
@@ -224,7 +224,7 @@ class file_storage {
     protected function create_converted_document(stored_file $file, $format) {
         global $CFG;
 
-        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
+        if (empty($CFG->pathtounoconv) || !file_is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return false;
         }
diff --git a/lib/tests/unoconv_test.php b/lib/tests/unoconv_test.php
index 3038abb3a5b..19817df320a 100644
--- a/lib/tests/unoconv_test.php
+++ b/lib/tests/unoconv_test.php
@@ -71,7 +71,7 @@ class core_unoconv_testcase extends advanced_testcase {
     public function test_generate_pdf() {
         global $CFG;
 
-        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
+        if (empty($CFG->pathtounoconv) || !file_is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return $this->markTestSkipped();
         }
@@ -90,7 +90,7 @@ class core_unoconv_testcase extends advanced_testcase {
     public function test_generate_markdown() {
         global $CFG;
 
-        if (empty($CFG->pathtounoconv) || !is_executable(trim($CFG->pathtounoconv))) {
+        if (empty($CFG->pathtounoconv) || !file_is_executable(trim($CFG->pathtounoconv))) {
             // No conversions are possible, sorry.
             return $this->markTestSkipped();
         }
diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 172d9c2eab7..78cd9490d17 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -115,7 +115,8 @@ information provided here is intended especially for developers.
   actual URLs in $text to encoded URLs in the @@PLUGINFILE@@ form.
 * behat_util::is_server_running() is removed, please use behat_util::check_server_status() instead.
 * Behat\Mink\Selector\SelectorsHandler::xpathLiteral() method is deprecated use behat_context_helper::escape instead
-  when building Xpath, or pass the unescaped value when using the named selector.',
+  when building Xpath, or pass the unescaped value when using the named selector.
+* Add new file_is_executable(), to consistently check for executables even in Windows (PHP bug #41062).
 
 === 3.0 ===