diff --git a/libguac/include/guacio.h b/libguac/include/guacio.h
index 86dcd22a..8b57f981 100644
--- a/libguac/include/guacio.h
+++ b/libguac/include/guacio.h
@@ -74,6 +74,11 @@ typedef struct GUACIO {
      */
     int written;
 
+    /**
+     * The number of bytes written total, since this GUACIO was opened.
+     */
+    int total_written;
+
     /**
      * The main write buffer. Bytes written go here before being flushed
      * to the open file descriptor.
diff --git a/libguac/src/client.c b/libguac/src/client.c
index 89485565..1b132af6 100644
--- a/libguac/src/client.c
+++ b/libguac/src/client.c
@@ -291,6 +291,9 @@ void guac_start_client(guac_client* client) {
         /* Handle server messages */
         if (client->handle_messages) {
 
+            /* Get previous GUACIO state */
+            int last_total_written = io->total_written;
+
             /* Only handle messages if synced within threshold */
             if (last_sent_timestamp - last_received_timestamp < 200) {
 
@@ -300,9 +303,11 @@ void guac_start_client(guac_client* client) {
                     return;
                 }
 
-                /* Send sync after updates */
-                last_sent_timestamp = __guac_current_timestamp();
-                guac_send_sync(io, last_sent_timestamp);
+                /* If data was written during message handling */
+                if (io->total_written != last_total_written) {
+                    last_sent_timestamp = __guac_current_timestamp();
+                    guac_send_sync(io, last_sent_timestamp);
+                }
 
                 guac_flush(io);
             }
diff --git a/libguac/src/guacio.c b/libguac/src/guacio.c
index c7135cd3..902c84fb 100644
--- a/libguac/src/guacio.c
+++ b/libguac/src/guacio.c
@@ -126,6 +126,7 @@ ssize_t guac_write_string(GUACIO* io, const char* str) {
     for (; *str != '\0'; str++) {
 
         out_buf[io->written++] = *str; 
+        io->total_written++;
 
         /* Flush when necessary, return on error */
         if (io->written > 8188 /* sizeof(out_buf) - 4 */) {
@@ -152,23 +153,28 @@ ssize_t __guac_write_base64_triplet(GUACIO* io, int a, int b, int c) {
 
     /* Byte 1 */
     out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[(a & 0xFC) >> 2]; /* [AAAAAA]AABBBB BBBBCC CCCCCC */
+    io->total_written++;
 
     if (b >= 0) {
         out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[((a & 0x03) << 4) | ((b & 0xF0) >> 4)]; /* AAAAAA[AABBBB]BBBBCC CCCCCC */
+        io->total_written++;
 
         if (c >= 0) {
             out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[((b & 0x0F) << 2) | ((c & 0xC0) >> 6)]; /* AAAAAA AABBBB[BBBBCC]CCCCCC */
             out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[c & 0x3F]; /* AAAAAA AABBBB BBBBCC[CCCCCC] */
+            io->total_written += 2;
         }
         else { 
             out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[((b & 0x0F) << 2)]; /* AAAAAA AABBBB[BBBB--]------ */
             out_buf[io->written++] = '='; /* AAAAAA AABBBB BBBB--[------] */
+            io->total_written += 2;
         }
     }
     else {
         out_buf[io->written++] = __GUACIO_BASE64_CHARACTERS[((a & 0x03) << 4)]; /* AAAAAA[AA----]------ ------ */
         out_buf[io->written++] = '='; /* AAAAAA AA----[------]------ */
         out_buf[io->written++] = '='; /* AAAAAA AA---- ------[------] */
+        io->total_written += 3;
     }
 
     /* At this point, 4 bytes have been io->written */