diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index cf1590d4..24a0c317 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -66,6 +66,7 @@ class Up2k(object):
         self.n_tagq = 0
         self.volstate = {}
         self.need_rescan = {}
+        self.dupesched = {}
         self.registry = {}
         self.entags = {}
         self.flags = {}
@@ -1121,8 +1122,14 @@ class Up2k(object):
                         continue
 
                     dp_abs = "/".join([cj["ptop"], dp_dir, dp_fn])
-                    # relying on path.exists to return false on broken symlinks
-                    if bos.path.exists(dp_abs):
+                    # relying on this to fail on broken symlinks
+                    try:
+                        sz = bos.path.getsize(dp_abs)
+                    except:
+                        sz = 0
+
+                    if sz:
+                        # self.log("--- " + wark + "  " + dp_abs + " found file", 4)
                         job = {
                             "name": dp_fn,
                             "prel": dp_dir,
@@ -1137,6 +1144,7 @@ class Up2k(object):
                         }
 
                 if job and wark in reg:
+                    # self.log("pop " + wark + "  " + job["name"] + " handle_json db", 4)
                     del reg[wark]
 
             if job or wark in reg:
@@ -1165,7 +1173,15 @@ class Up2k(object):
                         self.log("unfinished:\n  {0}\n  {1}".format(src, dst))
                         err = "partial upload exists at a different location; please resume uploading here instead:\n"
                         err += "/" + vsrc + " "
+
+                        dupe = [cj["prel"], cj["name"]]
+                        try:
+                            self.dupesched[src].append(dupe)
+                        except:
+                            self.dupesched[src] = [dupe]
+
                         raise Pebkac(400, err)
+
                     elif "nodupe" in self.flags[job["ptop"]]:
                         self.log("dupe-reject:\n  {0}\n  {1}".format(src, dst))
                         err = "upload rejected, file already exists:\n/" + vsrc + " "
@@ -1357,6 +1373,7 @@ class Up2k(object):
             except Exception as ex:
                 return "finish_upload, wark, " + repr(ex)
 
+            # self.log("--- " + wark + "  " + dst + " finish_upload atomic " + dst, 4)
             atomic_move(src, dst)
 
             if ANYWIN:
@@ -1366,9 +1383,28 @@ class Up2k(object):
             a = [job[x] for x in "ptop wark prel name lmod size addr".split()]
             a += [job.get("at") or time.time()]
             if self.idx_wark(*a):
+                # self.log("pop " + wark + "  " + dst + " finish_upload idx_wark", 4)
                 del self.registry[ptop][wark]
                 # in-memory registry is reserved for unfinished uploads
 
+            dupes = self.dupesched.pop(dst, [])
+            if not dupes:
+                return
+
+            cur = self.cur.get(ptop)
+            for rd, fn in dupes:
+                d2 = os.path.join(ptop, rd, fn)
+                if os.path.exists(d2):
+                    continue
+
+                self._symlink(dst, d2)
+                if cur:
+                    self.db_rm(cur, rd, fn)
+                    self.db_add(cur, wark, rd, fn, *a[-4:])
+
+            if cur:
+                cur.connection.commit()
+
     def idx_wark(self, ptop, wark, rd, fn, lmod, sz, ip, at):
         cur = self.cur.get(ptop)
         if not cur:
diff --git a/copyparty/web/up2k.js b/copyparty/web/up2k.js
index d5c0d3c9..661f08f5 100644
--- a/copyparty/web/up2k.js
+++ b/copyparty/web/up2k.js
@@ -1081,11 +1081,6 @@ function up2k_init(subtle) {
             st.busy.handshake.length)
             return false;
 
-        if (st.busy.handshake.length)
-            for (var n = t.n - 1; n >= t.n - parallel_uploads && n >= 0; n--)
-                if (st.files[n].t_uploading)
-                    return false;
-
         if ((uc.multitask ? 1 : 0) <
             st.todo.upload.length +
             st.busy.upload.length)
@@ -1138,6 +1133,17 @@ function up2k_init(subtle) {
                         st.busy.handshake.length +
                         st.busy.upload.length;
 
+                if (was_busy && !is_busy) {
+                    for (var a = 0; a < st.files.length; a++) {
+                        var t = st.files[a];
+                        if (t.want_recheck) {
+                            t.want_recheck = false;
+                            push_t(st.todo.handshake, t);
+                        }
+                    }
+                    is_busy = st.todo.handshake.length;
+                }
+
                 if (was_busy != is_busy) {
                     was_busy = is_busy;
 
@@ -1467,6 +1473,7 @@ function up2k_init(subtle) {
             }
 
             t.done = true;
+            t.fobj = null;
             st.bytes.hashed += t.size;
             st.bytes.finished += t.size;
             pvis.move(t.n, 'bz');
@@ -1551,6 +1558,7 @@ function up2k_init(subtle) {
                     apop(st.busy.handshake, t);
                     st.bytes.finished += t.size;
                     t.done = true;
+                    t.fobj = null;
                     tasker();
                     return;
                 }
@@ -1617,6 +1625,7 @@ function up2k_init(subtle) {
 
                 if (done) {
                     t.done = true;
+                    t.fobj = null;
                     st.bytes.finished += t.size - t.bytes_uploaded;
                     var spd1 = (t.size / ((t.t_hashed - t.t_hashing) / 1000.)) / (1024 * 1024.),
                         spd2 = (t.size / ((t.t_uploaded - t.t_uploading) / 1000.)) / (1024 * 1024.);
@@ -1651,13 +1660,19 @@ function up2k_init(subtle) {
                 }
 
                 st.bytes.finished += t.size;
-                if (rsp.indexOf('partial upload exists') !== -1 ||
-                    rsp.indexOf('file already exists') !== -1) {
+                var err_pend = rsp.indexOf('partial upload exists') + 1,
+                    err_dupe = rsp.indexOf('file already exists') + 1;
+
+                if (err_pend || err_dupe) {
                     err = rsp;
                     ofs = err.indexOf('\n/');
                     if (ofs !== -1) {
                         err = err.slice(0, ofs + 1) + linksplit(err.slice(ofs + 2).trimEnd()).join(' ');
                     }
+                    if (!t.rechecks && err_pend) {
+                        t.rechecks = 0;
+                        t.want_recheck = true;
+                    }
                 }
                 if (err != "") {
                     pvis.seth(t.n, 1, "ERROR");
@@ -1755,7 +1770,7 @@ function up2k_init(subtle) {
                 if (crashed)
                     return;
 
-                toast.err(9, "failed to upload a chunk,\n" + tries + " retries so far -- retrying in 10sec\n\n" + t.name);
+                toast.err(9.98, "failed to upload a chunk,\n" + tries + " retries so far -- retrying in 10sec\n\n" + t.name);
                 console.log('chunkpit onerror,', ++tries, t);
                 setTimeout(do_send, 10 * 1000);
             };