diff --git a/chain/sync.go b/chain/sync.go
index 0e5f1a126..1b1cbdde9 100644
--- a/chain/sync.go
+++ b/chain/sync.go
@@ -123,6 +123,8 @@ type Syncer struct {
 	receiptTracker *blockReceiptTracker
 
 	verifier ffiwrapper.Verifier
+
+	windowSize int
 }
 
 // NewSyncer creates a new Syncer object.
@@ -148,6 +150,7 @@ func NewSyncer(sm *stmgr.StateManager, bsync *blocksync.BlockSync, connmgr connm
 		receiptTracker: newBlockReceiptTracker(),
 		connmgr:        connmgr,
 		verifier:       verifier,
+		windowSize:     defaultMessageFetchWindowSize,
 
 		incoming: pubsub.New(50),
 	}
@@ -1413,7 +1416,8 @@ func (syncer *Syncer) iterFullTipsets(ctx context.Context, headers []*types.TipS
 
 	span.AddAttributes(trace.Int64Attribute("num_headers", int64(len(headers))))
 
-	windowSize := defaultMessageFetchWindowSize
+	windowSize := syncer.windowSize
+mainLoop:
 	for i := len(headers) - 1; i >= 0; {
 		fts, err := syncer.store.TryFillTipSet(headers[i])
 		if err != nil {
@@ -1441,6 +1445,12 @@ func (syncer *Syncer) iterFullTipsets(ctx context.Context, headers []*types.TipS
 			nreq := batchSize - len(bstout)
 			bstips, err := syncer.Bsync.GetChainMessages(ctx, next, uint64(nreq))
 			if err != nil {
+				// TODO check errors for temporary nature
+				if windowSize > 1 {
+					windowSize /= 2
+					log.Infof("error fetching messages: %s; reducing window size to %d and trying again", err, windowSize)
+					continue mainLoop
+				}
 				return xerrors.Errorf("message processing failed: %w", err)
 			}
 
@@ -1475,9 +1485,24 @@ func (syncer *Syncer) iterFullTipsets(ctx context.Context, headers []*types.TipS
 				return xerrors.Errorf("message processing failed: %w", err)
 			}
 		}
+
+		if i >= windowSize {
+			newWindowSize := windowSize + 10
+			if newWindowSize > int(blocksync.MaxRequestLength) {
+				newWindowSize = int(blocksync.MaxRequestLength)
+			}
+			if newWindowSize > windowSize {
+				windowSize = newWindowSize
+				log.Infof("successfully fetched %d messages; increasing window size to %d", len(bstout), windowSize)
+			}
+		}
+
 		i -= batchSize
 	}
 
+	// remember our window size
+	syncer.windowSize = windowSize
+
 	return nil
 }