diff --git a/artifacts/api-server/src/routes/executive-meetings.ts b/artifacts/api-server/src/routes/executive-meetings.ts
index b9ca05fd..6295b136 100644
--- a/artifacts/api-server/src/routes/executive-meetings.ts
+++ b/artifacts/api-server/src/routes/executive-meetings.ts
@@ -2908,9 +2908,17 @@ const upsertFontSettingsHandler = async (
     }
   }
   const targetUserId = data.scope === "global" ? null : userId;
-  // Logo is a brand asset and only lives on the global row. Per-user
-  // PATCHes silently drop the field rather than 400-ing so a generic
-  // "save my prefs" UI doesn't have to special-case the toggle.
+  // Logo is a brand asset and only lives on the global row. Reject
+  // user-scope writes that try to set a non-null logo so callers get
+  // a clear error instead of a silent no-op. `null` (explicit clear)
+  // and `undefined` (field not provided) are both fine on user rows.
+  if (data.scope === "user" && data.logoObjectPath != null) {
+    res.status(400).json({
+      error: "logoObjectPath is only allowed on the global font-settings row",
+      code: "logo_user_scope_forbidden",
+    });
+    return;
+  }
   const logoForWrite = data.scope === "global" ? data.logoObjectPath : undefined;
   const result = await db.transaction(async (tx) => {
     const [existing] = await tx
diff --git a/artifacts/api-server/tests/executive-meetings.test.mjs b/artifacts/api-server/tests/executive-meetings.test.mjs
index f577a010..7abca605 100644
--- a/artifacts/api-server/tests/executive-meetings.test.mjs
+++ b/artifacts/api-server/tests/executive-meetings.test.mjs
@@ -696,6 +696,49 @@ test("Font settings: valid combo 200; invalid weight/size/family 400", async ()
   assert.equal(badFamily.status, 400);
 });
 
+test("Font settings: user-scope rejects logoObjectPath with 400; null is allowed", async () => {
+  // User-scope writes that try to set a non-null logo path must be
+  // rejected loudly. The brand logo is a global asset; silently
+  // dropping the field would mislead callers into thinking their
+  // upload was saved.
+  const rejected = await api(
+    adminCookie,
+    "PUT",
+    "/api/executive-meetings/font-settings",
+    {
+      scope: "user",
+      fontFamily: "system",
+      fontSize: 14,
+      fontWeight: "regular",
+      alignment: "start",
+      fontColor: "#000000",
+      logoObjectPath: "/objects/some-fake-id",
+    },
+  );
+  assert.equal(rejected.status, 400);
+  const body = await rejected.json();
+  assert.equal(body.code, "logo_user_scope_forbidden");
+
+  // Explicit null (i.e. "I'm not setting a logo") must still work
+  // on the user row so a generic prefs UI doesn't have to omit the
+  // field.
+  const okNull = await api(
+    adminCookie,
+    "PUT",
+    "/api/executive-meetings/font-settings",
+    {
+      scope: "user",
+      fontFamily: "system",
+      fontSize: 14,
+      fontWeight: "regular",
+      alignment: "start",
+      fontColor: "#000000",
+      logoObjectPath: null,
+    },
+  );
+  assert.equal(okNull.status, 200);
+});
+
 test("PDF archives: POST creates a snapshot and GET returns it", async () => {
   const post = await api(
     adminCookie,