diff --git a/src/lib/__tests__/calendar-participants.test.ts b/src/lib/__tests__/calendar-participants.test.ts
index d7d56889..0ed5301c 100644
--- a/src/lib/__tests__/calendar-participants.test.ts
+++ b/src/lib/__tests__/calendar-participants.test.ts
@@ -349,6 +349,17 @@ describe('answers on save (Stalwart 0.16 and 1.0)', () => {
     ]);
   });
 
+  it('writes no blank names', () => {
+    const map = buildParticipantMap({ name: '', email: 'me@example.com' }, [
+      { name: '  ', email: 'bob@example.com' },
+      { name: ' Carol ', email: 'carol@example.com' },
+    ]);
+    const byEmail = Object.fromEntries(Object.values(map).map((p) => [p.email, p]));
+    expect(byEmail['me@example.com']).not.toHaveProperty('name');
+    expect(byEmail['bob@example.com']).not.toHaveProperty('name');
+    expect(byEmail['carol@example.com'].name).toBe('Carol');
+  });
+
   it('tells whether anyone but the organizer answered', () => {
     expect(hasAnsweredAttendees(meeting.participants)).toBe(true);
     expect(hasAnsweredAttendees(participantsAskedAgain(meeting))).toBe(false);
diff --git a/src/lib/calendar-participants.ts b/src/lib/calendar-participants.ts
index 666f510a..063a2e2d 100644
--- a/src/lib/calendar-participants.ts
+++ b/src/lib/calendar-participants.ts
@@ -355,9 +355,12 @@ export function buildParticipantMap(
   // stored as an inert JSPROP, so it is intentionally not sent.
   const organizerKey = organizer.email.trim().toLowerCase();
   const organizerStatus = known.get(organizerKey)?.status;
+  // A blank name is left out: written, it reaches the attendees' copies as
+  // an empty CN.
+  const organizerName = organizer.name?.trim();
   participants[idFor(organizerKey)] = {
     '@type': 'Participant',
-    name: organizer.name,
+    ...(organizerName ? { name: organizerName } : {}),
     email: organizer.email,
     calendarAddress: `mailto:${organizer.email}`,
     // owner only, NOT attendee: with roles.attendee set, Stalwart's server-side
@@ -380,9 +383,10 @@ export function buildParticipantMap(
     if (!key || seen.has(key)) return;
     seen.add(key);
 
+    const name = a.name?.trim();
     participants[idFor(key)] = {
       '@type': 'Participant',
-      name: a.name,
+      ...(name ? { name } : {}),
       email,
       calendarAddress: `mailto:${email}`,
       roles: { attendee: true },