diff --git a/pkg/state/storage.go b/pkg/state/storage.go
index 68b7e217..3a471c98 100644
--- a/pkg/state/storage.go
+++ b/pkg/state/storage.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/url"
 	"path/filepath"
+	"runtime"
 	"sort"
 	"strings"
 
@@ -135,11 +136,18 @@ func (st *Storage) normalizePath(path string) string {
 	if u != nil && (u.Scheme != "" || filepath.IsAbs(path)) {
 		return path
 	} else {
-		return st.JoinBase(path)
+		return st.JoinBase(path, runtime.GOOS)
 	}
 }
 
 // JoinBase returns an absolute path in the form basePath/relative
-func (st *Storage) JoinBase(relPath string) string {
-	return filepath.Join(st.basePath, relPath)
+// Helm's setFiles command does not support unescaped filepath separators (\) on Windows.
+// Instead, it requires double backslashes (\\) as filepath separators.
+// See https://github.com/helm/helm/issues/9537
+func (st *Storage) JoinBase(relPath, GOOS string) string {
+	path := filepath.Join(st.basePath, relPath)
+	if GOOS == "windows" {
+		return strings.ReplaceAll(path, "\\", "\\\\")
+	}
+	return path
 }
diff --git a/pkg/state/storage_test.go b/pkg/state/storage_test.go
index 5cc349b3..6bf66ad0 100644
--- a/pkg/state/storage_test.go
+++ b/pkg/state/storage_test.go
@@ -176,27 +176,37 @@ func TestJoinBase(t *testing.T) {
 	tests := []struct {
 		name string
 		base string
+		goos string
 		path string
 		want string
 	}{
 		{
 			name: "joinBase with non-root base",
 			base: "/root",
+			goos: "linux",
 			path: "local/timespan-application.yml",
 			want: "/local/timespan-application.yml",
 		},
 		{
 			name: "joinBase with root path",
 			base: "/",
+			goos: "linux",
 			path: "data/timespan-application.yml",
 			want: "/data/timespan-application.yml",
 		},
+		{
+			name: "windows joinBase",
+			base: "",
+			goos: "windows",
+			path: "data\\timespan-application.yml",
+			want: "data\\\\timespan-application.yml",
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			storageIns := NewStorage(tt.base, helmexec.NewLogger(io.Discard, "debug"), filesystem.DefaultFileSystem())
-			if got := storageIns.JoinBase(tt.path); got != tt.want {
+			if got := storageIns.JoinBase(tt.path, tt.goos); got != tt.want {
 				t.Errorf("JoinBase() = %v, want %v", got, tt.want)
 			}
 		})