Index: trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java	(revision 13450)
+++ trunk/src/org/openstreetmap/josm/io/CertificateAmendment.java	(revision 13451)
@@ -108,9 +108,11 @@
         private final String winAlias;
         private final String macAlias;
-
-        NativeCertAmend(String winAlias, String macAlias, String filename, String sha256) {
+        private final String httpsWebSite;
+
+        NativeCertAmend(String winAlias, String macAlias, String filename, String sha256, String httpsWebSite) {
             super(filename, sha256);
             this.winAlias = Objects.requireNonNull(winAlias);
             this.macAlias = Objects.requireNonNull(macAlias);
+            this.httpsWebSite = Objects.requireNonNull(httpsWebSite);
         }
 
@@ -129,4 +131,13 @@
         public final String getMacAlias() {
             return macAlias;
+        }
+
+        /**
+         * Returns the https website we need to call to notify Windows we need its root certificate.
+         * @return the https website signed with this root CA
+         * @since 13451
+         */
+        public String getWebSite() {
+            return httpsWebSite;
         }
 
@@ -157,12 +168,15 @@
         new NativeCertAmend("Staat der Nederlanden Root CA - G2", "Staat der Nederlanden Root CA - G2",
                 "Staat_der_Nederlanden_Root_CA_-_G2.crt",
-                "668c83947da63b724bece1743c31a0e6aed0db8ec5b31be377bb784f91b6716f"),
+                "668c83947da63b724bece1743c31a0e6aed0db8ec5b31be377bb784f91b6716f",
+                "https://roottest-g2.pkioverheid.nl"),
         // Government of Netherlands
         new NativeCertAmend("Government of Netherlands G3", "Staat der Nederlanden Root CA - G3",
                 "Staat_der_Nederlanden_Root_CA_-_G3.crt",
-                "3c4fb0b95ab8b30032f432b86f535fe172c185d0fd39865837cf36187fa6f428"),
+                "3c4fb0b95ab8b30032f432b86f535fe172c185d0fd39865837cf36187fa6f428",
+                "https://roottest-g3.pkioverheid.nl"),
         // Trusted and used by French Government - https://www.certigna.fr/autorites/index.xhtml?ac=Racine#lracine
         new NativeCertAmend("Certigna", "Certigna", "Certigna.crt",
-                "e3b6a2db2ed7ce48842f7ac53241c7b71d54144bfb40c11f3f1d0b42f5eea12d"),
+                "e3b6a2db2ed7ce48842f7ac53241c7b71d54144bfb40c11f3f1d0b42f5eea12d",
+                "https://www.certigna.fr"),
     };
 
Index: trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 13450)
+++ trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 13451)
@@ -59,4 +59,5 @@
 import java.security.spec.X509EncodedKeySpec;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Enumeration;
@@ -64,4 +65,5 @@
 import java.util.Locale;
 import java.util.Properties;
+import java.util.concurrent.ExecutionException;
 
 import javax.swing.JOptionPane;
@@ -441,4 +443,17 @@
     public X509Certificate getX509Certificate(NativeCertAmend certAmend)
             throws KeyStoreException, NoSuchAlgorithmException, CertificateException, IOException {
+        // Make a web request to target site to force Windows to update if needed its trust root store from its certificate trust list
+        // A better, but a lot more complex method might be to get certificate list from Windows Registry with PowerShell
+        // using (Get-ItemProperty -Path 'HKLM:\\SOFTWARE\\Microsoft\\SystemCertificates\\AuthRoot\\AutoUpdate').EncodedCtl)
+        // then decode it using CertUtil -dump or calling CertCreateCTLContext API using JNI, and finally find and decode the certificate
+        try {
+            // https://stackoverflow.com/a/41618979/2257172
+            Utils.execOutput(Arrays.asList("powershell", "-Command",
+                    "[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;" +
+                    "Invoke-WebRequest " + certAmend.getWebSite()));
+        } catch (ExecutionException | InterruptedException e) {
+            Logging.error(e);
+        }
+        // Get Windows Trust Root Store
         KeyStore ks = getRootKeystore();
         // Search by alias (fast)