diff --git a/src/Avatar.js b/src/Avatar.js
index 5a330c31e9..217b196348 100644
--- a/src/Avatar.js
+++ b/src/Avatar.js
@@ -102,6 +102,8 @@ export function getInitialLetter(name) {
 }
 
 export function avatarUrlForRoom(room, width, height, resizeMethod) {
+    if (!room) return null; // null-guard
+
     const explicitRoomAvatar = room.getAvatarUrl(
         MatrixClientPeg.get().getHomeserverUrl(),
         width,
diff --git a/src/editor/parts.js b/src/editor/parts.js
index 652342405f..8bb4f8633e 100644
--- a/src/editor/parts.js
+++ b/src/editor/parts.js
@@ -254,8 +254,8 @@ class RoomPillPart extends PillPart {
         let initialLetter = "";
         let avatarUrl = Avatar.avatarUrlForRoom(this._room, 16 * window.devicePixelRatio, 16 * window.devicePixelRatio);
         if (!avatarUrl) {
-            initialLetter = Avatar.getInitialLetter(this._room.name);
-            avatarUrl = `../../${Avatar.defaultAvatarUrlForString(this._room.roomId)}`;
+            initialLetter = Avatar.getInitialLetter(this._room ? this._room.name : this.resourceId);
+            avatarUrl = `../../${Avatar.defaultAvatarUrlForString(this._room ? this._room.roomId : this.resourceId)}`;
         }
         this._setAvatarVars(node, avatarUrl, initialLetter);
     }