diff --git a/aggregator/aggregator.go b/aggregator/aggregator.go
index 6b847d8fa..78ba1d014 100644
--- a/aggregator/aggregator.go
+++ b/aggregator/aggregator.go
@@ -29,6 +29,7 @@ import (
 	"math"
 	"os"
 	"path"
+	"path/filepath"
 	"regexp"
 	"sort"
 	"strconv"
@@ -217,7 +218,7 @@ func (cf *ChangeFile) openFile(blockNum uint64, write bool) error {
 	startBlock := blockNum - rem
 	endBlock := startBlock + cf.step - 1
 	if cf.w == nil {
-		cf.path = path.Join(cf.dir, fmt.Sprintf("%s.%d-%d.chg", cf.namebase, startBlock, endBlock))
+		cf.path = filepath.Join(cf.dir, fmt.Sprintf("%s.%d-%d.chg", cf.namebase, startBlock, endBlock))
 		var err error
 		if write {
 			if cf.file, err = os.OpenFile(cf.path, os.O_RDWR|os.O_CREATE, 0755); err != nil {
@@ -636,10 +637,10 @@ func (i *AggregateItem) Less(than btree.Item) bool {
 }
 
 func (c *Changes) produceChangeSets(blockFrom, blockTo uint64, historyType, bitmapType FileType) (*compress.Decompressor, *recsplit.Index, *compress.Decompressor, *recsplit.Index, error) {
-	chsetDatPath := path.Join(c.dir, fmt.Sprintf("%s.%d-%d.dat", historyType.String(), blockFrom, blockTo))
-	chsetIdxPath := path.Join(c.dir, fmt.Sprintf("%s.%d-%d.idx", historyType.String(), blockFrom, blockTo))
-	bitmapDatPath := path.Join(c.dir, fmt.Sprintf("%s.%d-%d.dat", bitmapType.String(), blockFrom, blockTo))
-	bitmapIdxPath := path.Join(c.dir, fmt.Sprintf("%s.%d-%d.idx", bitmapType.String(), blockFrom, blockTo))
+	chsetDatPath := filepath.Join(c.dir, fmt.Sprintf("%s.%d-%d.dat", historyType.String(), blockFrom, blockTo))
+	chsetIdxPath := filepath.Join(c.dir, fmt.Sprintf("%s.%d-%d.idx", historyType.String(), blockFrom, blockTo))
+	bitmapDatPath := filepath.Join(c.dir, fmt.Sprintf("%s.%d-%d.dat", bitmapType.String(), blockFrom, blockTo))
+	bitmapIdxPath := filepath.Join(c.dir, fmt.Sprintf("%s.%d-%d.idx", bitmapType.String(), blockFrom, blockTo))
 	var blockSuffix [8]byte
 	binary.BigEndian.PutUint64(blockSuffix[:], blockTo)
 	bitmaps := map[string]*roaring64.Bitmap{}