diff --git a/src/file.cc b/src/file.cc
index 64373095..9c5f23ab 100644
--- a/src/file.cc
+++ b/src/file.cc
@@ -148,6 +148,7 @@ StringView homedir()
 
 bool fd_readable(int fd)
 {
+    kak_assert(fd >= 0);
     fd_set  rfds;
     FD_ZERO(&rfds);
     FD_SET(fd, &rfds);
@@ -158,6 +159,7 @@ bool fd_readable(int fd)
 
 bool fd_writable(int fd)
 {
+    kak_assert(fd >= 0);
     fd_set  wfds;
     FD_ZERO(&wfds);
     FD_SET(fd, &wfds);
diff --git a/src/remote.cc b/src/remote.cc
index 5490a7b6..be793f0b 100644
--- a/src/remote.cc
+++ b/src/remote.cc
@@ -439,7 +439,8 @@ RemoteUI::~RemoteUI()
     // Try to send the remaining data if possible, as it might contain the desired exit status
     try
     {
-        send_data(m_socket_watcher.fd(), m_send_buffer);
+        if (m_socket_watcher.fd() != -1)
+            send_data(m_socket_watcher.fd(), m_send_buffer);
     }
     catch (disconnected&)
     {