diff --git a/src/common.h b/src/common.h
index be21c9fe6..4e3b61ca2 100644
--- a/src/common.h
+++ b/src/common.h
@@ -962,6 +962,8 @@ void assert_is_not_forked_child(const char *who);
 /// and checking if "Microsoft" is in the first line.
 /// See https://github.com/Microsoft/WSL/issues/423 and Microsoft/WSL#2997
 constexpr bool is_windows_subsystem_for_linux() {
+    // This function is called after fork() and before exec() in postfork.cpp. Make sure we
+    // don't allocate any memory here!
 #ifdef WSL
     return true;
 #else
diff --git a/src/postfork.cpp b/src/postfork.cpp
index fd4a4f320..ae006cf92 100644
--- a/src/postfork.cpp
+++ b/src/postfork.cpp
@@ -106,6 +106,11 @@ bool child_set_group(job_t *j, process_t *p) {
                 1, "Could not send own process %s, '%s' in job %s, '%s' from group %s to group %s",
                 pid_buff, argv0, job_id_buff, command, getpgid_buff, job_pgid_buff);
 
+            if (is_windows_subsystem_for_linux() && errno == EPERM) {
+                debug_safe(1, "Please update to Windows 10 1809/17763 or higher to address known issues "
+                        "with process groups and zombie processes.");
+            }
+
             safe_perror("setpgid");
 
             return false;