diff --git a/src/httprpc.cpp b/src/httprpc.cpp
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -7,7 +7,6 @@
 #include <chainparams.h>
 #include <config.h>
 #include <crypto/hmac_sha256.h>
-#include <node/ui_interface.h>
 #include <rpc/protocol.h>
 #include <util/ref.h>
 #include <util/strencodings.h>
@@ -403,11 +402,6 @@
     if (gArgs.GetArg("-rpcpassword", "") == "") {
         LogPrintf("Using random cookie authentication.\n");
         if (!GenerateAuthCookie(&strRPCUserColonPass)) {
-            // Same message as AbortNode.
-            uiInterface.ThreadSafeMessageBox(
-                _("Error: A fatal internal error occurred, see debug.log for "
-                  "details"),
-                "", CClientUIInterface::MSG_ERROR);
             return false;
         }
     } else {
diff --git a/src/httpserver.cpp b/src/httpserver.cpp
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -460,7 +460,7 @@
 #endif
 }
 
-static std::thread threadHTTP;
+static std::thread g_thread_http;
 static std::vector<std::thread> g_thread_http_workers;
 
 void StartHTTPServer() {
@@ -468,7 +468,7 @@
     int rpcThreads =
         std::max((long)gArgs.GetArg("-rpcthreads", DEFAULT_HTTP_THREADS), 1L);
     LogPrintf("HTTP: starting %d worker threads\n", rpcThreads);
-    threadHTTP = std::thread(ThreadHTTP, eventBase);
+    g_thread_http = std::thread(ThreadHTTP, eventBase);
 
     for (int i = 0; i < rpcThreads; i++) {
         g_thread_http_workers.emplace_back(HTTPWorkQueueRun, workQueue, i);
@@ -505,7 +505,9 @@
     boundSockets.clear();
     if (eventBase) {
         LogPrint(BCLog::HTTP, "Waiting for HTTP event thread to exit\n");
-        threadHTTP.join();
+        if (g_thread_http.joinable()) {
+            g_thread_http.join();
+        }
     }
     if (eventHTTP) {
         evhttp_free(eventHTTP);
diff --git a/test/functional/rpc_users.py b/test/functional/rpc_users.py
--- a/test/functional/rpc_users.py
+++ b/test/functional/rpc_users.py
@@ -98,9 +98,7 @@
                                 password + 'wrong').status)
 
     def run_test(self):
-        ##################################################
-        # Check correctness of the rpcauth config option #
-        ##################################################
+        self.log.info('Check correctness of the rpcauth config option')
         url = urllib.parse.urlparse(self.nodes[0].url)
 
         self.test_auth(self.nodes[0], url.username, url.password)
@@ -108,13 +106,23 @@
         self.test_auth(self.nodes[0], 'rt2', self.rt2password)
         self.test_auth(self.nodes[0], self.user, self.password)
 
-        ###############################################################
-        # Check correctness of the rpcuser/rpcpassword config options #
-        ###############################################################
+        self.log.info(
+            'Check correctness of the rpcuser/rpcpassword config options')
         url = urllib.parse.urlparse(self.nodes[1].url)
 
         self.test_auth(self.nodes[1], self.rpcuser, self.rpcpassword)
 
+        self.log.info(
+            'Check that failure to write cookie file will abort the node gracefully')
+        self.stop_node(0)
+        cookie_file = os.path.join(
+            get_datadir_path(self.options.tmpdir, 0),
+            self.chain,
+            '.cookie.tmp')
+        os.mkdir(cookie_file)
+        init_error = 'Error: Unable to start HTTP server. See debug log for details.'
+        self.nodes[0].assert_start_raises_init_error(expected_msg=init_error)
+
 
 if __name__ == '__main__':
     HTTPBasicsTest().main()