diff --git a/go/pkg/cas/upload.go b/go/pkg/cas/upload.go
index 14d84e8..ea3bc58 100644
--- a/go/pkg/cas/upload.go
+++ b/go/pkg/cas/upload.go
@@ -220,6 +220,9 @@
 	if !filepath.IsAbs(ps.Path) {
 		return errors.Errorf("%q is not absolute", ps.Path)
 	}
+	cpy := *ps
+	ps = &cpy
+	ps.Path = filepath.Clean(ps.Path)
 
 	// Schedule a file system walk.
 	u.wgFS.Add(1)