diff --git a/go/model/qscod/fs/store/store.go b/go/model/qscod/fs/store/store.go
index 8405c4c..87e80a1 100644
--- a/go/model/qscod/fs/store/store.go
+++ b/go/model/qscod/fs/store/store.go
@@ -102,9 +102,9 @@ func (fs *FileStore) tryWriteRead(step Step, v Value) (Value, Head, error) {
 	}
 
 	// Try to write it to the versioned store -
-	// but don't fret if someone else wrote it first.
+	// but don't fret if someone else wrote it or if it has expired.
 	err = fs.state.WriteVersion(ver, string(buf))
-	if err != nil && !verst.IsExist(err) {
+	if err != nil && !verst.IsExist(err) && !verst.IsNotExist(err) {
 		return Value{}, Head{}, err
 	}
 
diff --git a/go/model/qscod/fs/verst/state.go b/go/model/qscod/fs/verst/state.go
index 7b833fa..719bea6 100644
--- a/go/model/qscod/fs/verst/state.go
+++ b/go/model/qscod/fs/verst/state.go
@@ -168,7 +168,7 @@ func (st *State) refresh() error {
 }
 
 // Scan a directory for highest-numbered file or subdirectory matching format.
-// If upTo > 0, then returns the highest-numbered version no higher than upTo.
+// If upTo > 0, returns the highest-numbered version no higher than upTo.
 func scan(path, format string, upTo Version) (
 	maxver Version, maxname string, names []string, err error) {