diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index a631a016a3..5787991f07 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -142,6 +142,9 @@ func main() {
 	}
 
 	runtime_init() // must be before defer
+	if nanotime() == 0 {
+		throw("nanotime returning zero")
+	}
 
 	// Defer unlock so that runtime.Goexit during init does the unlock too.
 	needUnlock := true
diff --git a/src/runtime/time.go b/src/runtime/time.go
index abf200d7d3..23f61d62d0 100644
--- a/src/runtime/time.go
+++ b/src/runtime/time.go
@@ -309,4 +309,10 @@ func time_runtimeNano() int64 {
 	return nanotime()
 }
 
-var startNano int64 = nanotime()
+// Monotonic times are reported as offsets from startNano.
+// We initialize startNano to nanotime() - 1 so that on systems where
+// monotonic time resolution is fairly low (e.g. Windows 2008
+// which appears to have a default resolution of 15ms),
+// we avoid ever reporting a nanotime of 0.
+// (Callers may want to use 0 as "time not set".)
+var startNano int64 = nanotime() - 1