diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index 0abf6ccb3..352feb720 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -130,7 +130,6 @@ struct curlFileTransfer : public FileTransfer
 
         ~TransferItem()
         {
-            curl_multi_remove_handle(fileTransfer.curlm, req);
             curl_easy_cleanup(req);
             if (requestHeaders) curl_slist_free_all(requestHeaders);
             try {
@@ -517,6 +516,21 @@ struct curlFileTransfer : public FileTransfer
             lock->unpause.push_back(shared_from_this());
             fileTransfer.wakeup();
         }
+
+        void cancel()
+        {
+            std::promise<void> promise;
+            auto wait = promise.get_future();
+            {
+                auto lock = fileTransfer.state_.lock();
+                if (lock->quit) {
+                    return;
+                }
+                lock->cancel[shared_from_this()] = std::move(promise);
+            }
+            fileTransfer.wakeup();
+            wait.get();
+        }
     };
 
     struct State
@@ -529,6 +543,7 @@ struct curlFileTransfer : public FileTransfer
         bool quit = false;
         std::priority_queue<std::shared_ptr<TransferItem>, std::vector<std::shared_ptr<TransferItem>>, EmbargoComparator> incoming;
         std::vector<std::shared_ptr<TransferItem>> unpause;
+        std::map<std::shared_ptr<TransferItem>, std::promise<void>> cancel;
     };
 
     Sync<State> state_;
@@ -605,6 +620,14 @@ struct curlFileTransfer : public FileTransfer
         while (!quit) {
             checkInterrupt();
 
+            {
+                auto cancel = [&] { return std::move(state_.lock()->cancel); }();
+                for (auto & [item, promise] : cancel) {
+                    curl_multi_remove_handle(curlm, item->req);
+                    promise.set_value();
+                }
+            }
+
             /* Let curl do its thing. */
             int running;
             CURLMcode mc = curl_multi_perform(curlm, &running);
@@ -826,7 +849,7 @@ struct curlFileTransfer : public FileTransfer
         }
 
         struct State {
-            bool done = false, failed = false;
+            bool done = false;
             std::exception_ptr exc;
             std::string data;
             std::condition_variable avail;
@@ -848,11 +871,6 @@ struct curlFileTransfer : public FileTransfer
             [_state](std::string_view data) {
                 auto state(_state->lock());
 
-                if (state->failed) {
-                    // actual exception doesn't matter, the other end is already dead
-                    throw std::exception{};
-                }
-
                 /* If the buffer is full, then go to sleep until the calling
                 thread wakes us up (i.e. when it has removed data from the
                 buffer). We don't wait forever to prevent stalling the
@@ -890,10 +908,8 @@ struct curlFileTransfer : public FileTransfer
             ~TransferSource()
             {
                 // wake up the download thread if it's still going and have it abort
-                auto state(_state->lock());
-                state->failed |= !state->done;
                 try {
-                    transfer->unpause();
+                    transfer->cancel();
                 } catch (...) {
                     ignoreExceptionInDestructor();
                 }