diff --git a/src/node/handler/PadMessageHandler.js b/src/node/handler/PadMessageHandler.js
index 7ea5039d..86244d85 100644
--- a/src/node/handler/PadMessageHandler.js
+++ b/src/node/handler/PadMessageHandler.js
@@ -1629,10 +1629,14 @@ function composePadChangesets(padId, startNum, endNum, callback)
       changeset = changesets[startNum];
       var pool = pad.apool();
 
-      for(var r=startNum+1;r<endNum;r++)
-      {
-        var cs = changesets[r];
-        changeset = Changeset.compose(changeset, cs, pool);
+      try {
+        for(var r=startNum+1;r<endNum;r++) {
+          var cs = changesets[r];
+          changeset = Changeset.compose(changeset, cs, pool);
+        }
+      } catch(e){
+        console.warn("failed to compose cs in pad:",padId);
+        return;
       }
 
       callback(null);
diff --git a/src/static/js/Changeset.js b/src/static/js/Changeset.js
index df180f9c..c97756b8 100644
--- a/src/static/js/Changeset.js
+++ b/src/static/js/Changeset.js
@@ -1318,7 +1318,7 @@ exports.compose = function (cs1, cs2, pool) {
   var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked1.newLen;
-  exports.assert(len2 == unpacked2.oldLen, "mismatched composition of two changesets");
+  exports.assert(len2 == unpacked2.oldLen, "mismatched composition of two changesets - cs1:",cs1," and cs2:",cs2);
   var len3 = unpacked2.newLen;
   var bankIter1 = exports.stringIterator(unpacked1.charBank);
   var bankIter2 = exports.stringIterator(unpacked2.charBank);