diff --git a/backup/converter/convertlib.php b/backup/converter/convertlib.php
index ef37f5ea3ca..efcd6230658 100644
--- a/backup/converter/convertlib.php
+++ b/backup/converter/convertlib.php
@@ -239,15 +239,17 @@ abstract class base_converter implements loggable {
     protected function replace_tempdir() {
         global $CFG;
 
+        $tempdir = $this->get_tempdir_path();
+
         if (empty($CFG->keeptempdirectoriesonbackup)) {
-            fulldelete($this->get_tempdir_path());
+            fulldelete($tempdir);
         } else {
-            if (!rename($this->get_tempdir_path(), $this->get_tempdir_path()  . '_' . $this->get_name() . '_' . $this->id . '_source')) {
+            if (!rename($tempdir, $tempdir . '_' . $this->get_name() . '_' . $this->id . '_source')) {
                 throw new convert_exception('failed_rename_source_tempdir');
             }
         }
 
-        if (!rename($this->get_workdir_path(), $this->get_tempdir_path())) {
+        if (!rename($this->get_workdir_path(), $tempdir)) {
             throw new convert_exception('failed_move_converted_into_place');
         }
     }
diff --git a/privacy/classes/local/request/moodle_content_writer.php b/privacy/classes/local/request/moodle_content_writer.php
index 2e82e6a4f42..bf25a061a14 100644
--- a/privacy/classes/local/request/moodle_content_writer.php
+++ b/privacy/classes/local/request/moodle_content_writer.php
@@ -162,7 +162,7 @@ class moodle_content_writer implements content_writer {
      * @return  string                      The processed string
      */
     public function rewrite_pluginfile_urls(array $subcontext, $component, $filearea, $itemid, $text) : string {
-        return str_replace('@@PLUGINFILE@@/', $this->get_files_target_path($component, $filearea, $itemid).'/', $text);
+        return str_replace('@@PLUGINFILE@@/', $this->get_files_target_url($component, $filearea, $itemid).'/', $text);
     }
 
     /**
@@ -272,7 +272,9 @@ class moodle_content_writer implements content_writer {
         // Join the directory together with the name.
         $filepath = implode(DIRECTORY_SEPARATOR, $path) . DIRECTORY_SEPARATOR . $name;
 
-        return preg_replace('@' . DIRECTORY_SEPARATOR . '+@', DIRECTORY_SEPARATOR, $filepath);
+        // To use backslash, it must be doubled ("\\\\" PHP string).
+        $separator = str_replace('\\', '\\\\', DIRECTORY_SEPARATOR);
+        return preg_replace('@(' . $separator . '|/)+@', $separator, $filepath);
     }
 
     /**
@@ -291,7 +293,9 @@ class moodle_content_writer implements content_writer {
         // Join the directory together with the name.
         $filepath = implode(DIRECTORY_SEPARATOR, $path);
 
-        return preg_replace('@' . DIRECTORY_SEPARATOR . '+@', DIRECTORY_SEPARATOR, $filepath);
+        // To use backslash, it must be doubled ("\\\\" PHP string).
+        $separator = str_replace('\\', '\\\\', DIRECTORY_SEPARATOR);
+        return preg_replace('@(' . $separator . '|/)+@', $separator, $filepath);
     }
 
     /**
@@ -314,6 +318,25 @@ class moodle_content_writer implements content_writer {
         return implode(DIRECTORY_SEPARATOR, $parts);
     }
 
+    /**
+     * Get a relative url to the directory of the exported files within a subcontext.
+     *
+     * @param string $component The name of the component that the files belong to.
+     * @param string $filearea The filearea within that component.
+     * @param string $itemid Which item those files belong to.
+     * @return string The url
+     */
+    protected function get_files_target_url($component, $filearea, $itemid) : string {
+        // We do not need to include the component because we organise things by context.
+        $parts = ['_files', $filearea];
+
+        if (!empty($itemid)) {
+            $parts[] = $itemid;
+        }
+
+        return implode('/', $parts);
+    }
+
     /**
      * Write the data to the specified path.
      *
diff --git a/privacy/classes/tests/request/content_writer.php b/privacy/classes/tests/request/content_writer.php
index d46ae39e854..93c7026da80 100644
--- a/privacy/classes/tests/request/content_writer.php
+++ b/privacy/classes/tests/request/content_writer.php
@@ -411,7 +411,10 @@ class content_writer implements \core_privacy\local\request\content_writer {
      */
     public function export_file(array $subcontext, \stored_file $file) : \core_privacy\local\request\content_writer  {
         if (!$file->is_directory()) {
-            $filepath = explode(DIRECTORY_SEPARATOR, $file->get_filepath());
+            $filepath = $file->get_filepath();
+            // Directory separator in the stored_file class should always be '/'. The following line is just a fail safe.
+            $filepath = str_replace(DIRECTORY_SEPARATOR, '/', $filepath);
+            $filepath = explode('/', $filepath);
             $filepath[] = $file->get_filename();
             $filepath = array_filter($filepath);
             $filepath = implode('/', $filepath);
diff --git a/privacy/tests/moodle_content_writer_test.php b/privacy/tests/moodle_content_writer_test.php
index 7e81a3d2cfa..f4ccc3bd66b 100644
--- a/privacy/tests/moodle_content_writer_test.php
+++ b/privacy/tests/moodle_content_writer_test.php
@@ -1162,12 +1162,18 @@ class moodle_content_writer_test extends advanced_testcase {
         if (null === $subcontext) {
             $rcm = $rc->getMethod('get_context_path');
             $rcm->setAccessible(true);
-            return $rcm->invoke($writer);
+            $path = $rcm->invoke($writer);
         } else {
             $rcm = $rc->getMethod('get_path');
             $rcm->setAccessible(true);
-            return $rcm->invoke($writer, $subcontext, $name);
+            $path = $rcm->invoke($writer, $subcontext, $name);
         }
+
+        // PHPUnit uses mikey179/vfsStream which is a stream wrapper for a virtual file system that uses '/'
+        // as the directory separator.
+        $path = str_replace(DIRECTORY_SEPARATOR, '/', $path);
+
+        return $path;
     }
 
     /**