diff --git a/src/openvpn/error.c b/src/openvpn/error.c
index b0e9a48c..5da588d9 100644
--- a/src/openvpn/error.c
+++ b/src/openvpn/error.c
@@ -242,7 +242,25 @@ x_msg_va(const unsigned int flags, const char *format, va_list arglist)
         return;
     }
 
-    e = openvpn_errno();
+    bool use_strerr = false;
+#ifdef _WIN32
+    if (flags & M_WSAERR)
+    {
+        e = WSAGetLastError();
+    }
+    else
+    {
+        e = GetLastError();
+        if (e == ERROR_SUCCESS)
+        {
+            /* error is likely C runtime, fallback to errno/strerr */
+            use_strerr = true;
+            e = errno;
+        }
+    }
+#else
+    e = errno;
+#endif
 
     /*
      * Apply muting filter.
@@ -264,7 +282,7 @@ x_msg_va(const unsigned int flags, const char *format, va_list arglist)
     if ((flags & M_ERRNO) && e)
     {
         openvpn_snprintf(m2, ERR_BUF_SIZE, "%s: %s (errno=%d)",
-                         m1, strerror(e), e);
+                         m1, use_strerr ? strerror(e) : openvpn_strerror(e, &gc), e);
         SWAP;
     }
 
@@ -678,13 +696,13 @@ x_check_status(int status,
             {
                 msg(x_cs_info_level, "%s %s [%s]: %s (fd=%d,code=%d)", description,
                     sock ? proto2ascii(sock->info.proto, sock->info.af, true) : "",
-                    extended_msg, strerror(my_errno), sock ? sock->sd : -1, my_errno);
+                    extended_msg, openvpn_strerror(my_errno, &gc), sock ? sock->sd : -1, my_errno);
             }
             else
             {
                 msg(x_cs_info_level, "%s %s: %s (fd=%d,code=%d)", description,
                     sock ? proto2ascii(sock->info.proto, sock->info.af, true) : "",
-                    strerror(my_errno), sock ? sock->sd : -1, my_errno);
+                    openvpn_strerror(my_errno, &gc), sock ? sock->sd : -1, my_errno);
             }
 
             if (x_cs_err_delay_ms)
diff --git a/src/openvpn/error.h b/src/openvpn/error.h
index ad7defe8..9c3f4dfb 100644
--- a/src/openvpn/error.h
+++ b/src/openvpn/error.h
@@ -99,9 +99,18 @@ extern int x_msg_line_num;
 #define M_NONFATAL        (1<<5)         /* non-fatal error */
 #define M_WARN            (1<<6)         /* call syslog with LOG_WARNING */
 #define M_DEBUG           (1<<7)
-
 #define M_ERRNO           (1<<8)         /* show errno description */
 
+#ifdef _WIN32
+#define M_WSAERR          (1<<9)         /* WinSock errors */
+#endif
+
+#ifdef _WIN32
+#define M_SKERR           (M_ERRNO | M_WSAERR) /* socket errors */
+#else
+#define M_SKERR           M_ERRNO
+#endif
+
 #define M_NOMUTE          (1<<11)        /* don't do mute processing */
 #define M_NOPREFIX        (1<<12)        /* don't show date/time prefix */
 #define M_USAGE_SMALL     (1<<13)        /* fatal options error, call usage_small */
diff --git a/src/openvpn/manage.c b/src/openvpn/manage.c
index 496042a6..2fa508ef 100644
--- a/src/openvpn/manage.c
+++ b/src/openvpn/manage.c
@@ -1890,13 +1890,13 @@ man_connect(struct management *man)
 #if UNIX_SOCK_SUPPORT
         if (man->settings.flags & MF_UNIX_SOCK)
         {
-            msg(D_LINK_ERRORS | M_ERRNO,
+            msg(D_LINK_ERRORS | M_SKERR,
                 "MANAGEMENT: connect to unix socket %s failed",
                 sockaddr_unix_name(&man->settings.local_unix, "NULL"));
         }
         else
 #endif
-        msg(D_LINK_ERRORS | M_ERRNO,
+        msg(D_LINK_ERRORS | M_SKERR,
             "MANAGEMENT: connect to %s failed",
             print_sockaddr(man->settings.local->ai_addr, &gc));
         throw_signal_soft(SIGTERM, "management-connect-failed");
diff --git a/src/openvpn/mtu.c b/src/openvpn/mtu.c
index aa810f1c..45398953 100644
--- a/src/openvpn/mtu.c
+++ b/src/openvpn/mtu.c
@@ -407,7 +407,7 @@ set_sock_extended_error_passing(int sd)
     int on = 1;
     if (setsockopt(sd, SOL_IP, IP_RECVERR, (void *) &on, sizeof(on)))
     {
-        msg(M_WARN | M_ERRNO,
+        msg(M_WARN | M_SKERR,
             "Note: enable extended error passing on TCP/UDP socket failed (IP_RECVERR)");
     }
 }
diff --git a/src/openvpn/platform.c b/src/openvpn/platform.c
index 450f28ba..1aafd604 100644
--- a/src/openvpn/platform.c
+++ b/src/openvpn/platform.c
@@ -532,7 +532,7 @@ platform_test_file(const char *filename)
         }
         else
         {
-            if (openvpn_errno() == EACCES)
+            if (errno == EACCES)
             {
                 msg( M_WARN | M_ERRNO, "Could not access file '%s'", filename);
             }
diff --git a/src/openvpn/proxy.c b/src/openvpn/proxy.c
index ed720161..409bc4af 100644
--- a/src/openvpn/proxy.c
+++ b/src/openvpn/proxy.c
@@ -110,7 +110,7 @@ recv_line(socket_descriptor_t sd,
         {
             if (verbose)
             {
-                msg(D_LINK_ERRORS | M_ERRNO, "recv_line: TCP port read timeout expired");
+                msg(D_LINK_ERRORS | M_SKERR, "recv_line: TCP port read timeout expired");
             }
             goto error;
         }
@@ -120,7 +120,7 @@ recv_line(socket_descriptor_t sd,
         {
             if (verbose)
             {
-                msg(D_LINK_ERRORS | M_ERRNO, "recv_line: TCP port read failed on select()");
+                msg(D_LINK_ERRORS | M_SKERR, "recv_line: TCP port read failed on select()");
             }
             goto error;
         }
@@ -133,7 +133,7 @@ recv_line(socket_descriptor_t sd,
         {
             if (verbose)
             {
-                msg(D_LINK_ERRORS | M_ERRNO, "recv_line: TCP port read failed on recv()");
+                msg(D_LINK_ERRORS | M_SKERR, "recv_line: TCP port read failed on recv()");
             }
             goto error;
         }
@@ -199,7 +199,7 @@ send_line(socket_descriptor_t sd,
     const ssize_t size = send(sd, buf, strlen(buf), MSG_NOSIGNAL);
     if (size != (ssize_t) strlen(buf))
     {
-        msg(D_LINK_ERRORS | M_ERRNO, "send_line: TCP port write failed on send()");
+        msg(D_LINK_ERRORS | M_SKERR, "send_line: TCP port write failed on send()");
         return false;
     }
     return true;
diff --git a/src/openvpn/ps.c b/src/openvpn/ps.c
index 9dca53c8..64cc1ed3 100644
--- a/src/openvpn/ps.c
+++ b/src/openvpn/ps.c
@@ -429,7 +429,7 @@ proxy_entry_new(struct proxy_connection **list,
     /* connect to port share server */
     if ((sd_server = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
     {
-        msg(M_WARN|M_ERRNO, "PORT SHARE PROXY: cannot create socket");
+        msg(M_WARN|M_SKERR, "PORT SHARE PROXY: cannot create socket");
         return false;
     }
     status = openvpn_connect(sd_server,(const struct sockaddr *)  &server_addr, 5, NULL);
diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index 0f34a5de..acfcfd65 100644
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -1143,7 +1143,7 @@ create_socket(struct link_socket *sock, struct addrinfo *addr)
         msg(M_INFO, "Using bind-dev %s", sock->bind_dev);
         if (setsockopt(sock->sd, SOL_SOCKET, SO_BINDTODEVICE, sock->bind_dev, strlen(sock->bind_dev) + 1) != 0)
         {
-            msg(M_WARN|M_ERRNO, "WARN: setsockopt SO_BINDTODEVICE=%s failed", sock->bind_dev);
+            msg(M_WARN|M_SKERR, "WARN: setsockopt SO_BINDTODEVICE=%s failed", sock->bind_dev);
         }
 
     }
@@ -1222,7 +1222,7 @@ socket_do_accept(socket_descriptor_t sd,
 
         if (!socket_defined(new_sd))
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "TCP: getpeername() failed");
+            msg(D_LINK_ERRORS | M_SKERR, "TCP: getpeername() failed");
         }
         else
         {
@@ -1247,7 +1247,7 @@ socket_do_accept(socket_descriptor_t sd,
 
     if (!socket_defined(new_sd))
     {
-        msg(D_LINK_ERRORS | M_ERRNO, "TCP: accept(%d) failed", (int)sd);
+        msg(D_LINK_ERRORS | M_SKERR, "TCP: accept(%d) failed", (int)sd);
     }
     /* only valid if we have remote_len_af!=0 */
     else if (remote_len_af && remote_len != remote_len_af)
@@ -1313,7 +1313,7 @@ socket_listen_accept(socket_descriptor_t sd,
 
         if (status < 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "TCP: select() failed");
+            msg(D_LINK_ERRORS | M_SKERR, "TCP: select() failed");
         }
 
         if (status <= 0)
@@ -1409,12 +1409,12 @@ socket_bind(socket_descriptor_t sd,
         msg(M_INFO, "setsockopt(IPV6_V6ONLY=%d)", v6only);
         if (setsockopt(sd, IPPROTO_IPV6, IPV6_V6ONLY, (void *) &v6only, sizeof(v6only)))
         {
-            msg(M_NONFATAL|M_ERRNO, "Setting IPV6_V6ONLY=%d failed", v6only);
+            msg(M_NONFATAL | M_SKERR, "Setting IPV6_V6ONLY=%d failed", v6only);
         }
     }
     if (bind(sd, cur->ai_addr, cur->ai_addrlen))
     {
-        msg(M_FATAL | M_ERRNO, "%s: Socket bind failed on local address %s",
+        msg(M_FATAL | M_SKERR, "%s: Socket bind failed on local address %s",
             prefix,
             print_sockaddr_ex(local->ai_addr, ":", PS_SHOW_PORT, &gc));
     }
@@ -2254,7 +2254,7 @@ link_socket_close(struct link_socket *sock)
                 msg(D_LOW, "TCP/UDP: Closing socket");
                 if (openvpn_close_socket(sock->sd))
                 {
-                    msg(M_WARN | M_ERRNO, "TCP/UDP: Close Socket failed");
+                    msg(M_WARN | M_SKERR, "TCP/UDP: Close Socket failed");
                 }
             }
             sock->sd = SOCKET_UNDEFINED;
@@ -2271,7 +2271,7 @@ link_socket_close(struct link_socket *sock)
         {
             if (openvpn_close_socket(sock->ctrl_sd))
             {
-                msg(M_WARN | M_ERRNO, "TCP/UDP: Close Socket (ctrl_sd) failed");
+                msg(M_WARN | M_SKERR, "TCP/UDP: Close Socket (ctrl_sd) failed");
             }
             sock->ctrl_sd = SOCKET_UNDEFINED;
         }
@@ -3668,7 +3668,7 @@ sockethandle_finalize(sockethandle_t sh,
                     /* if no error (i.e. just not finished yet), then DON'T execute this code */
                     io->iostate = IOSTATE_INITIAL;
                     ASSERT(ResetEvent(io->overlapped.hEvent));
-                    msg(D_WIN32_IO | M_ERRNO, "WIN32 I/O: Completion error");
+                    msg(D_WIN32_IO | SocketHandleErrorFlag(sh), "WIN32 I/O: Completion error");
                 }
             }
             break;
@@ -3681,7 +3681,7 @@ sockethandle_finalize(sockethandle_t sh,
                 /* error return for a non-queued operation */
                 SocketHandleSetLastError(sh, io->status);
                 ret = -1;
-                msg(D_WIN32_IO | M_ERRNO, "WIN32 I/O: Completion non-queued error");
+                msg(D_WIN32_IO | SocketHandleErrorFlag(sh), "WIN32 I/O: Completion non-queued error");
             }
             else
             {
diff --git a/src/openvpn/socket.h b/src/openvpn/socket.h
index e9f1524d..a7ec827a 100644
--- a/src/openvpn/socket.h
+++ b/src/openvpn/socket.h
@@ -301,6 +301,12 @@ SocketHandleSetInvalError(sockethandle_t sh)
     sh.is_handle ? SetLastError(ERROR_INVALID_FUNCTION) : WSASetLastError(WSAEINVAL);
 }
 
+static inline int
+SocketHandleErrorFlag(sockethandle_t sh)
+{
+    return sh.is_handle ? M_ERRNO : M_SKERR;
+}
+
 #else  /* ifdef _WIN32 */
 
 #define openvpn_close_socket(s) close(s)
diff --git a/src/openvpn/socks.c b/src/openvpn/socks.c
index 768bb613..10107c18 100644
--- a/src/openvpn/socks.c
+++ b/src/openvpn/socks.c
@@ -117,7 +117,7 @@ socks_username_password_auth(struct socks_proxy_info *p,
 
     if (size != strlen(to_send))
     {
-        msg(D_LINK_ERRORS | M_ERRNO, "socks_username_password_auth: TCP port write failed on send()");
+        msg(D_LINK_ERRORS | M_SKERR, "socks_username_password_auth: TCP port write failed on send()");
         goto cleanup;
     }
 
@@ -145,14 +145,14 @@ socks_username_password_auth(struct socks_proxy_info *p,
         /* timeout? */
         if (status == 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_username_password_auth: TCP port read timeout expired");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_username_password_auth: TCP port read timeout expired");
             goto cleanup;
         }
 
         /* error */
         if (status < 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_username_password_auth: TCP port read failed on select()");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_username_password_auth: TCP port read failed on select()");
             goto cleanup;
         }
 
@@ -162,7 +162,7 @@ socks_username_password_auth(struct socks_proxy_info *p,
         /* error? */
         if (size != 1)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_username_password_auth: TCP port read failed on recv()");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_username_password_auth: TCP port read failed on recv()");
             goto cleanup;
         }
 
@@ -204,7 +204,7 @@ socks_handshake(struct socks_proxy_info *p,
     size = send(sd, method_sel, sizeof(method_sel), MSG_NOSIGNAL);
     if (size != sizeof(method_sel))
     {
-        msg(D_LINK_ERRORS | M_ERRNO, "socks_handshake: TCP port write failed on send()");
+        msg(D_LINK_ERRORS | M_SKERR, "socks_handshake: TCP port write failed on send()");
         return false;
     }
 
@@ -232,14 +232,14 @@ socks_handshake(struct socks_proxy_info *p,
         /* timeout? */
         if (status == 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_handshake: TCP port read timeout expired");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_handshake: TCP port read timeout expired");
             return false;
         }
 
         /* error */
         if (status < 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_handshake: TCP port read failed on select()");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_handshake: TCP port read failed on select()");
             return false;
         }
 
@@ -249,7 +249,7 @@ socks_handshake(struct socks_proxy_info *p,
         /* error? */
         if (size != 1)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "socks_handshake: TCP port read failed on recv()");
+            msg(D_LINK_ERRORS | M_SKERR, "socks_handshake: TCP port read failed on recv()");
             return false;
         }
 
@@ -342,14 +342,14 @@ recv_socks_reply(socket_descriptor_t sd,
         /* timeout? */
         if (status == 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "recv_socks_reply: TCP port read timeout expired");
+            msg(D_LINK_ERRORS | M_SKERR, "recv_socks_reply: TCP port read timeout expired");
             return false;
         }
 
         /* error */
         if (status < 0)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "recv_socks_reply: TCP port read failed on select()");
+            msg(D_LINK_ERRORS | M_SKERR, "recv_socks_reply: TCP port read failed on select()");
             return false;
         }
 
@@ -359,7 +359,7 @@ recv_socks_reply(socket_descriptor_t sd,
         /* error? */
         if (size != 1)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "recv_socks_reply: TCP port read failed on recv()");
+            msg(D_LINK_ERRORS | M_SKERR, "recv_socks_reply: TCP port read failed on recv()");
             return false;
         }
 
@@ -484,7 +484,7 @@ establish_socks_proxy_passthru(struct socks_proxy_info *p,
         const ssize_t size = send(sd, buf, 5 + len + 2, MSG_NOSIGNAL);
         if ((int)size != 5 + (int)len + 2)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "establish_socks_proxy_passthru: TCP port write failed on send()");
+            msg(D_LINK_ERRORS | M_SKERR, "establish_socks_proxy_passthru: TCP port write failed on send()");
             goto error;
         }
     }
@@ -527,7 +527,7 @@ establish_socks_proxy_udpassoc(struct socks_proxy_info *p,
                                   10, MSG_NOSIGNAL);
         if (size != 10)
         {
-            msg(D_LINK_ERRORS | M_ERRNO, "establish_socks_proxy_passthru: TCP port write failed on send()");
+            msg(D_LINK_ERRORS | M_SKERR, "establish_socks_proxy_passthru: TCP port write failed on send()");
             goto error;
         }
     }