diff --git a/output.cc b/output.cc
index a5c7bfa..a52bbc1 100644
--- a/output.cc
+++ b/output.cc
@@ -1537,8 +1537,10 @@ static void printosclassificationoutput(const struct
             int flen = strlen(familygenerations[familyno]);
             // We add it, preceded by | if something is already there
             if (flen + 2 + strlen(OSR->OSC[classno]->OS_Generation) >=
-                sizeof(familygenerations[familyno]))
-              fatal("buffer 0verfl0w of familygenerations");
+                sizeof(familygenerations[familyno])) {
+              fatal("buffer 0verfl0w of familygenerations \"%s\" \"%s\"",
+		familygenerations[familyno], OSR->OSC[classno]->OS_Generation);
+            }
             if (*familygenerations[familyno])
               strcat(familygenerations[familyno], "|");
             strncat(familygenerations[familyno],