diff --git a/README.md b/README.md
index ab32b86..7b7034a 100644
--- a/README.md
+++ b/README.md
@@ -1467,6 +1467,8 @@ Important: The specified value must be the value that is stored in the database,
 * For dropdown fields, you may need to view the HTML code to see what the actual values are for a field.
 * For checkboxes, the checked value is 1, unchecked is 0.
 
+Reminder: When logged out (or in as guest), user profile fields do not exist. Therefore, "not" will always evaluate to true and "is", "contains" and "in" will evaluate to false.
+
 ### What are the supported dateTimeFormat formats?
 
 The date and time formats, defined in Moodle (langconfig.php)[https://github.com/moodle/moodle/blob/master/lang/en/langconfig.php], control how dates and times will be displayed.
diff --git a/filter.php b/filter.php
index 13004ad..2aa2a50 100644
--- a/filter.php
+++ b/filter.php
@@ -3939,15 +3939,22 @@ function ($matches) use ($USER) {
                 if ($found > 0) {
                     foreach ($matches[1] as $key => $match) {
                         $fieldname = $matches[1][$key];
-                        // Do not process tag if the specified profile field name does not exist.
-                        if (!array_key_exists($fieldname, $profilefields)) {
-                            continue;
-                        }
-
                         $string = $matches[0][$key]; // String found in $text.
                         $operator = $matches[2][$key];
                         $value = $matches[3][$key];
 
+                        // Do not process tag if the specified profile field name does not exist or user is not logged in.
+                        if (!array_key_exists($fieldname, $profilefields) || !isloggedin() || isguestuser()) {
+                            if ($operator == 'not') {
+                                // It will always meet criteria of a "not" if the user doesn't have a profile.
+                                $replace['/' . preg_quote($string, '/') . '/isuU'] = $matches[4][$key];
+                            } else {
+                                // It will never match the criteria "is", "contains" or "in" if the user doesn't have a profile.
+                                $replace['/' . preg_quote($string, '/') . '/isuU'] = '';
+                            }
+                            continue;
+                        }
+
                         if (!empty($value)) {
                             $value = trim($value, '"'); // Trim quotation marks.
                         }
diff --git a/version.php b/version.php
index 62d16d8..8d1a04d 100644
--- a/version.php
+++ b/version.php
@@ -25,7 +25,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2024072200;            // The current plugin version (Date: YYYYMMDDXX).
+$plugin->version   = 2024072201;            // The current plugin version (Date: YYYYMMDDXX).
 $plugin->requires  = 2014051200;            // Requires Moodle version 2.7 or later.
 $plugin->component = 'filter_filtercodes';  // Full name of the plugin (used for diagnostics).
 $plugin->release   = '2.5.2';