diff --git a/classes/cli_helper.php b/classes/cli_helper.php
index 7ba328f..ff42a9d 100644
--- a/classes/cli_helper.php
+++ b/classes/cli_helper.php
@@ -204,6 +204,10 @@ public function validate_and_clean_args(): void {
             }
         }
         if (isset($cliargs['ignorecat'])) {
+            // Allow escaping of forward slash at start in Windows.
+            if (strlen($cliargs['ignorecat']) > 1 && substr($cliargs['ignorecat'], 0, 2) === '//') {
+                $cliargs['ignorecat'] = substr($cliargs['ignorecat'], 1);
+            }
             if (@preg_match($cliargs['ignorecat'], 'zzzzzzzz') === false) {
                 echo "\nThere is a problem with your regular expression for ignoring categories:\n";
                 echo error_get_last()["message"] . "\n";
diff --git a/cli/createrepo.php b/cli/createrepo.php
index 6b8b4c8..7a9b9ad 100755
--- a/cli/createrepo.php
+++ b/cli/createrepo.php
@@ -142,7 +142,7 @@
     [
         'longopt' => 'ignorecat',
         'shortopt' => 'x',
-        'description' => 'Regex of categories to ignore',
+        'description' => 'Regex of categories to ignore - add an extra leading / for Windows.',
         'default' => $ignorecat,
         'variable' => 'ignorecat',
         'valuerequired' => true,
diff --git a/cli/deletefrommoodle.php b/cli/deletefrommoodle.php
index e4a2ca0..77d50d3 100755
--- a/cli/deletefrommoodle.php
+++ b/cli/deletefrommoodle.php
@@ -140,7 +140,7 @@
     [
         'longopt' => 'ignorecat',
         'shortopt' => 'x',
-        'description' => 'Regex of categories to ignore',
+        'description' => 'Regex of categories to ignore - add an extra leading / for Windows.',
         'default' => $ignorecat,
         'variable' => 'ignorecat',
         'valuerequired' => true,
diff --git a/cli/exportrepofrommoodle.php b/cli/exportrepofrommoodle.php
index 49c7a8f..a7491f0 100644
--- a/cli/exportrepofrommoodle.php
+++ b/cli/exportrepofrommoodle.php
@@ -100,7 +100,7 @@
     [
         'longopt' => 'ignorecat',
         'shortopt' => 'x',
-        'description' => 'Regex of categories to ignore',
+        'description' => 'Regex of categories to ignore - add an extra leading / for Windows.',
         'default' => $ignorecat,
         'variable' => 'ignorecat',
         'valuerequired' => true,
diff --git a/cli/importrepotomoodle.php b/cli/importrepotomoodle.php
index c4075fb..0689909 100755
--- a/cli/importrepotomoodle.php
+++ b/cli/importrepotomoodle.php
@@ -140,7 +140,7 @@
     [
         'longopt' => 'ignorecat',
         'shortopt' => 'x',
-        'description' => 'Regex of categories to ignore',
+        'description' => 'Regex of categories to ignore - add an extra leading / for Windows.',
         'default' => $ignorecat,
         'variable' => 'ignorecat',
         'valuerequired' => true,
diff --git a/doc/createrepo.md b/doc/createrepo.md
index 38dc8d0..d06ff9f 100644
--- a/doc/createrepo.md
+++ b/doc/createrepo.md
@@ -23,7 +23,7 @@
 |n|instanceid|Numerical id of the course, module of course category.
 |t|token|Security token for webservice.
 |h|help|
-|x|ignorecat|Regex of categories to ignore
+|x|ignorecat|Regex of categories to ignore - add an extra leading / for Windows.
 
 ### Example 1:
 
diff --git a/doc/deletefrommoodle.md b/doc/deletefrommoodle.md
index f99a655..b4eda15 100644
--- a/doc/deletefrommoodle.md
+++ b/doc/deletefrommoodle.md
@@ -25,7 +25,7 @@
 |n|instanceid|Numerical id of the course, module of course category.
 |t|token|Security token for webservice.
 |h|help|
-|x|ignorecat|Regex of categories to ignore
+|x|ignorecat|Regex of categories to ignore - add an extra leading / for Windows.
 
 Examples:
 
diff --git a/doc/exportrepofrommoodle.md b/doc/exportrepofrommoodle.md
index 2a84619..8336194 100644
--- a/doc/exportrepofrommoodle.md
+++ b/doc/exportrepofrommoodle.md
@@ -17,7 +17,7 @@
 |q|questioncategoryid|Numerical id of subcategory to actually export.
 |t|token|Security token for webservice.|
 |h|help|
-|x|ignorecat|Regex of categories to ignore
+|x|ignorecat|Regex of categories to ignore - add an extra leading / for Windows.
 
 Examples:
 
diff --git a/doc/importrepotomoodle.md b/doc/importrepotomoodle.md
index 24850ec..202f02b 100644
--- a/doc/importrepotomoodle.md
+++ b/doc/importrepotomoodle.md
@@ -28,7 +28,7 @@ Commit this update.
 |n|instanceid|Numerical id of the course, module of course category.
 |t|token|Security token for webservice.
 |h|help|
-|x|ignorecat|Regex of categories to ignore
+|x|ignorecat|Regex of categories to ignore - add an extra leading / for Windows.
 
 Examples:
 
diff --git a/doc/usinggit.md b/doc/usinggit.md
index e00de62..22ac505 100644
--- a/doc/usinggit.md
+++ b/doc/usinggit.md
@@ -35,7 +35,7 @@ You can use context instance id and subcategory id instead:
 * `-n` the context instance id, which is the course id in this case.
 * `-q` the question category id
 
-You can also ignore certain categories (and their descendants) using `-x` and a regex expression to match the category name(s) within Moodle.
+You can also ignore certain categories (and their descendants) using `-x` and a regex expression to match the category name(s) within Moodle. (Add an extra leading / in Windows e.g. "//^.*DO_NOT_SHARE$/".)
 
 `php createrepo.php -l course -n 2 -d "master" -q 80 -x "/^.*DO_NOT_SHARE$/"`
 
diff --git a/tests/cli_helper_test.php b/tests/cli_helper_test.php
index 9ad4a48..e67ebe8 100644
--- a/tests/cli_helper_test.php
+++ b/tests/cli_helper_test.php
@@ -504,6 +504,7 @@ public function test_validation_ignorecat(): void {
         $helper->processedoptions = ['token' => 'X', 'manifestpath' => 'path/subpath', 'ignorecat' => '/hello/'];
         $helper->validate_and_clean_args();
         $this->expectOutputString('');
+        $this->assertEquals('/hello/', $helper->processedoptions['ignorecat']);
     }
 
     /**
@@ -516,4 +517,16 @@ public function test_validation_ignorecat_error(): void {
         @$helper->validate_and_clean_args();
         $this->expectOutputRegex('/problem with your regular expression/');
     }
+
+    /**
+     * Validation
+     * @covers \gitsync\cli_helper\validate_and_clean_args()
+     */
+    public function test_validation_ignorecat_replace(): void {
+        $helper = new fake_cli_helper([]);
+        $helper->processedoptions = ['token' => 'X', 'manifestpath' => 'path/subpath', 'ignorecat' => '//hello\//'];
+        $helper->validate_and_clean_args();
+        $this->expectOutputString('');
+        $this->assertEquals('/hello\//', $helper->processedoptions['ignorecat']);
+    }
 }