diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index c91be22a47..32deec8a9b 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -100,6 +100,12 @@ module.exports = React.createClass({
     },
 
     componentWillUnmount: function() {
+        // set a boolean to say we've been unmounted, which any pending
+        // promises can use to throw away their results.
+        //
+        // (We could use isMounted, but facebook have deprecated that.)
+        this.unmounted = true;
+
         if (this.refs.messagePanel) {
             // disconnect the D&D event listeners from the message panel. This
             // is really just for hygiene - the messagePanel is going to be
@@ -196,7 +202,7 @@ module.exports = React.createClass({
     },*/
 
     onRoomTimeline: function(ev, room, toStartOfTimeline) {
-        if (!this.isMounted()) return;
+        if (this.unmounted) return;
 
         // ignore anything that comes in whilst paginating: we get one
         // event for each new matrix event so this would cause a huge
@@ -355,7 +361,7 @@ module.exports = React.createClass({
 
         // we might have switched rooms since the paginate started - just bin
         // the results if so.
-        if (!this.isMounted()) return;
+        if (this.unmounted) return;
 
         this.setState({
             room: MatrixClientPeg.get().getRoom(this.props.roomId),
@@ -538,7 +544,7 @@ module.exports = React.createClass({
 
         return searchPromise.then(function(results) {
             debuglog("search complete");
-            if (!this.isMounted() || !self.state.searching || self.searchId != localSearchId) {
+            if (self.unmounted || !self.state.searching || self.searchId != localSearchId) {
                 console.error("Discarding stale search results");
                 return;
             }
diff --git a/src/components/structures/ScrollPanel.js b/src/components/structures/ScrollPanel.js
index fc628b5a5e..8d26b2e365 100644
--- a/src/components/structures/ScrollPanel.js
+++ b/src/components/structures/ScrollPanel.js
@@ -112,6 +112,14 @@ module.exports = React.createClass({
         this.checkFillState();
     },
 
+    componentWillUnmount: function() {
+        // set a boolean to say we've been unmounted, which any pending
+        // promises can use to throw away their results.
+        //
+        // (We could use isMounted(), but facebook have deprecated that.)
+        this.unmounted = true;
+    },
+
     onScroll: function(ev) {
         var sn = this._getScrollNode();
         debuglog("Scroll event: offset now:", sn.scrollTop, "recentEventScroll:", this.recentEventScroll);
@@ -158,7 +166,7 @@ module.exports = React.createClass({
 
     // check the scroll state and send out backfill requests if necessary.
     checkFillState: function() {
-        if (!this.isMounted()) {
+        if (this.unmounted) {
             return;
         }
 
@@ -350,7 +358,7 @@ module.exports = React.createClass({
      * message panel.
      */
     _getScrollNode: function() {
-        if (!this.isMounted()) {
+        if (this.unmounted) {
             // this shouldn't happen, but when it does, turn the NPE into
             // something more meaningful.
             throw new Error("ScrollPanel._getScrollNode called when unmounted");