diff --git a/src/builder/b-nspawn.c b/src/builder/b-nspawn.c
index b0f1c2a..98036a8 100644
--- a/src/builder/b-nspawn.c
+++ b/src/builder/b-nspawn.c
@@ -89,9 +89,9 @@ callback_sai_stdwsi(struct lws *wsi, enum lws_callback_reasons reason,
 	switch (reason) {
 
 	case LWS_CALLBACK_RAW_CLOSE_FILE:
-		lwsl_info("%s: RAW_CLOSE_FILE at %llu, wsi %p: fd: %d, stdfd: %d\n",
-			  __func__, (unsigned long long)lws_now_usecs(), wsi,
-			  lws_get_socket_fd(wsi), lws_spawn_get_stdfd(wsi));
+		lwsl_info("%s: stdwsi CLOSE, ns %p, lsp: %p, wsi: %p, fd: %d, stdfd: %d\n",
+			  __func__, op ? op->ns : NULL, op ? op->lsp : NULL,
+			  wsi, lws_get_socket_fd(wsi), lws_spawn_get_stdfd(wsi));
 
 		ilen = lws_snprintf((char *)buf, sizeof(buf), "Stdwsi %d close\n", lws_spawn_get_stdfd(wsi));
 		if (ns) {
@@ -103,7 +103,11 @@ callback_sai_stdwsi(struct lws *wsi, enum lws_callback_reasons reason,
 		}
 
 		if (op && op->lsp) {
-			lws_spawn_stdwsi_closed(op->lsp, wsi);
+			if (lws_spawn_stdwsi_closed(op->lsp, wsi) &&
+			    ns->reap_cb_called) {
+				lwsl_notice("%s: freeing op from stdwsi_cb\n", __func__);
+				free(op);
+			}
 			if (ns)
 				lws_cancel_service(ns->builder->context);
 		}
@@ -338,9 +342,15 @@ skip:
 	saib_task_grace(ns);
 	saib_set_ns_state(ns, NSSTATE_DONE);
 
+	ns->reap_cb_called = 1;
+
 	if (ns)
 		ns->op = NULL;
-	free(op);
+
+	if (!op->lsp || lws_spawn_get_stdwsi_open_count(op->lsp) == 0) {
+		lwsl_notice("%s: freeing op from reap_cb\n", __func__);
+		free(op);
+	}
 
 	return;
 
@@ -589,6 +599,7 @@ saib_spawn_script(struct sai_nspawn *ns)
 	memset(op, 0, sizeof(*op));
 
 	op->ns = ns;
+	ns->reap_cb_called = 0;
 	ns->op = op;
 #if defined(WIN32)
 	op->spawn = _strdup(one_step);
diff --git a/src/builder/b-private.h b/src/builder/b-private.h
index 54608ca..25db3e0 100644
--- a/src/builder/b-private.h
+++ b/src/builder/b-private.h
@@ -139,7 +139,11 @@ struct sai_builder {
 	uint64_t		disk_total_kib;
 	uint64_t		disk_reserved_kib;
 
+#if !defined(WIN32)
 	int			pipe_master_wr;
+#else
+	void			*pipe_master_wr_win;
+#endif
 };
 
 struct jpargs {
diff --git a/src/builder/b-sai.c b/src/builder/b-sai.c
index f47cebe..75d35a7 100644
--- a/src/builder/b-sai.c
+++ b/src/builder/b-sai.c
@@ -957,13 +957,6 @@ int main(int argc, const char **argv)
 	if ((p = lws_cmdline_option(argc, argv, "-d")))
 		logs = atoi(p);
 
-	if ((p = lws_cmdline_option(argc, argv, "--home")))
-		/*
-		 * This is the deletion worker process being spawned, it only
-		 * needs to know the home dir to clean up inside
-		 */
-		return sai_deletion_worker(p);
-
 	if ((p = lws_cmdline_option(argc, argv, "-c")))
 		config_dir = p;
 
@@ -1012,9 +1005,6 @@ int main(int argc, const char **argv)
 		return 1;
 	}
 
-//	lwsl_notice("%s: parsed %s %s %s\n", __func__, builder.metrics_path,
-//			builder.metrics_uri, builder.metrics_secret);
-
 	/*
 	 * We need to sample the true uid / gid we should use inside
 	 * the mountpoint for sai:nobody or sai:sai, by looking at
@@ -1063,7 +1053,47 @@ int main(int argc, const char **argv)
 		builder.pipe_master_wr = pfd[1];
 	}
 #else
-	/* TODO: windows worker process spawn */
+	{
+		char cmdline[512];
+		HANDLE hChildStd_IN_Rd = NULL;
+		HANDLE hChildStd_IN_Wr = NULL;
+		SECURITY_ATTRIBUTES sa;
+		PROCESS_INFORMATION pi;
+		STARTUPINFOA si;
+
+		sa.nLength = sizeof(SECURITY_ATTRIBUTES);
+		sa.bInheritHandle = TRUE;
+		sa.lpSecurityDescriptor = NULL;
+
+		if (!CreatePipe(&hChildStd_IN_Rd, &hChildStd_IN_Wr, &sa, 0)) {
+			lwsl_err("CreatePipe failed\n");
+			return 1;
+		}
+		if (!SetHandleInformation(hChildStd_IN_Wr, HANDLE_FLAG_INHERIT, 0)) {
+			lwsl_err("SetHandleInformation failed\n");
+			return 1;
+		}
+
+		memset(&pi, 0, sizeof(pi));
+		memset(&si, 0, sizeof(si));
+		si.cb = sizeof(si);
+		si.hStdInput = hChildStd_IN_Rd;
+		si.dwFlags |= STARTF_USESTDHANDLES;
+
+		lws_snprintf(cmdline, sizeof(cmdline), "%s --delete-worker --home=%s",
+			     argv[0], builder.home);
+
+		if (!CreateProcessA(NULL, cmdline, NULL, NULL, TRUE, 0,
+				    NULL, NULL, &si, &pi)) {
+			lwsl_err("CreateProcess failed\n");
+			return 1;
+		}
+
+		CloseHandle(pi.hProcess);
+		CloseHandle(pi.hThread);
+		CloseHandle(hChildStd_IN_Rd);
+		builder.pipe_master_wr_win = hChildStd_IN_Wr;
+	}
 #endif
 
 #if defined(__linux__)
diff --git a/src/builder/b-task.c b/src/builder/b-task.c
index a75e216..d31f23b 100644
--- a/src/builder/b-task.c
+++ b/src/builder/b-task.c
@@ -403,10 +403,20 @@ saib_task_destroy(struct sai_nspawn *ns)
 
 		lwsl_notice("%s: task %s succeeded, requesting deletion of job dir %s\n",
 			    __func__, ns->task->uuid, ns->inp);
+#if !defined(WIN32)
 		if (write(builder.pipe_master_wr, ns->task->uuid,
 			  LWS_POSIX_LENGTH_CAST(strlen(ns->task->uuid))) != (ssize_t)strlen(ns->task->uuid))
 			lwsl_err("%s: failed to write to deletion worker\n",
 				 __func__);
+#else
+		{
+			DWORD written;
+			if (!WriteFile(builder.pipe_master_wr_win, ns->task->uuid,
+				       strlen(ns->task->uuid), &written, NULL))
+				lwsl_err("%s: failed to write to deletion worker\n",
+					 __func__);
+		}
+#endif
 	}
 
 	if (ns->task) {
diff --git a/src/common/include/private.h b/src/common/include/private.h
index 1b59f23..76d1c40 100644
--- a/src/common/include/private.h
+++ b/src/common/include/private.h
@@ -209,7 +209,7 @@ struct sai_nspawn {
 	uint8_t				finished_when_logs_drained:1;
 	uint8_t				state_changed:1;
 	uint8_t				user_cancel:1;
-
+	uint8_t				reap_cb_called:1;
 };
 
 /*
diff --git a/src/web/w-ws-browser.c b/src/web/w-ws-browser.c
index 0cd8436..1448ab2 100644
--- a/src/web/w-ws-browser.c
+++ b/src/web/w-ws-browser.c
@@ -1046,8 +1046,8 @@ enum_tasks:
 			t->art_up_nonce[0] = '\0';
 			t->art_down_nonce[0] = '\0';
 
-			t->rebuildable = t->state == SAIES_FAIL &&
-				(lws_now_secs() - (t->started + (t->duration / 1000000)) < 24 * 3600);
+			t->rebuildable = (t->state == SAIES_FAIL || t->state == SAIES_CANCELLED) &&
+				(lws_now_secs() - (t->started + t->duration / 1000000) < 24 * 3600);
 
 			/* only one in it at a time */
 			t = lws_container_of(task_owner.head, sai_task_t, list);
@@ -1210,7 +1210,8 @@ b_finish:
 
 		task_reply.event = sch->one_event;
 		task_reply.task = sch->one_task;
-		sch->one_task->rebuildable = sch->one_task->state == SAIES_FAIL &&
+		sch->one_task->rebuildable = (sch->one_task->state == SAIES_FAIL ||
+				sch->one_task->state == SAIES_CANCELLED) &&
 				(lws_now_secs() - (sch->one_task->started +
 						(sch->one_task->duration / 1000000)) < 24 * 3600);
 		task_reply.auth_secs = (int)(pss->authorized ? pss->expiry_unix_time - lws_now_secs() : 0);