diff --git a/server/e2e/proto_project_export_test.go b/server/e2e/proto_project_export_test.go
index c100586b22..50d8c0564d 100644
--- a/server/e2e/proto_project_export_test.go
+++ b/server/e2e/proto_project_export_test.go
@@ -1,7 +1,10 @@
 package e2e
 
 import (
+	"archive/zip"
+	"bytes"
 	"context"
+	"encoding/json"
 	"testing"
 
 	pb "github.com/reearth/reearth/server/internal/adapter/internalapi/schemas/internalapi/v1"
@@ -88,7 +91,8 @@ func TestInternalAPI_export(t *testing.T) {
 
 		resp.Header("Content-Type").Contains("application/zip")
 		body := resp.Body().Raw()
-		assert.Greater(t, len(body), 0)
+		assert.Greater(t, len(body), 4)
+		assert.Equal(t, "PK\x03\x04", string(body[:4])) // check zip file hedder
 
 		// private => Error!
 		exp, err = client.ExportProject(ctx, &pb.ExportProjectRequest{
@@ -131,7 +135,40 @@ func TestInternalAPI_export(t *testing.T) {
 
 		resp.Header("Content-Type").Contains("application/zip")
 		body := resp.Body().Raw()
-		assert.Greater(t, len(body), 0)
+		assert.Greater(t, len(body), 4)
+		assert.Equal(t, "PK\x03\x04", string(body[:4])) // zip header
+
+		data := []byte(body)
+
+		r, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+		require.NoError(t, err)
+
+		var pjBytes []byte
+		for _, f := range r.File {
+			if f.Name == "project.json" {
+				rc, err := f.Open()
+				require.NoError(t, err)
+
+				var buf bytes.Buffer
+				_, err = buf.ReadFrom(rc)
+				rc.Close()
+				require.NoError(t, err)
+
+				pjBytes = buf.Bytes()
+				break
+			}
+		}
+		require.NotNil(t, pjBytes, "project.json should exist in the zip")
+		assert.True(t, json.Valid(pjBytes), "project.json must be valid JSON")
+
+		var doc map[string]any
+		require.NoError(t, json.Unmarshal(pjBytes, &doc))
+
+		_, ok := doc["project"].(map[string]any)
+		assert.True(t, ok, "`project` must exist and be an object")
+
+		_, ok = doc["scene"].(map[string]any)
+		assert.True(t, ok, "`scene` must exist and be an object")
 
 	})
 }
diff --git a/server/internal/app/repo.go b/server/internal/app/repo.go
index 4409dea06d..5f4128ee94 100644
--- a/server/internal/app/repo.go
+++ b/server/internal/app/repo.go
@@ -167,6 +167,7 @@ func initReposAndGateways(ctx context.Context, conf *config.Config, debug bool)
 func initFile(ctx context.Context, conf *config.Config) (fileRepo gateway.File) {
 	var err error
 	if conf.GCS.IsConfigured() {
+		log.Infofc(ctx, "[Storage] GCS storage is used: %s", conf.GCS.BucketName)
 		isFake := conf.GCS.IsFake
 		fileRepo, err = gcs.NewFile(isFake, conf.GCS.BucketName, conf.AssetBaseURL, conf.GCS.PublicationCacheControl)
 		if err != nil {
@@ -177,7 +178,7 @@ func initFile(ctx context.Context, conf *config.Config) (fileRepo gateway.File)
 	}
 
 	if conf.S3.IsConfigured() {
-		log.Infofc(ctx, "file: S3 storage is used: %s\n", conf.S3.BucketName)
+		log.Infofc(ctx, "[Storage] S3 storage is used: %s", conf.S3.BucketName)
 		fileRepo, err = s3.NewS3(ctx, conf.S3.BucketName, conf.AssetBaseURL, conf.S3.PublicationCacheControl)
 		if err != nil {
 			log.Warnf("file: failed to init S3 storage: %s\n", err.Error())
@@ -185,7 +186,7 @@ func initFile(ctx context.Context, conf *config.Config) (fileRepo gateway.File)
 		return
 	}
 
-	log.Infof("file: local storage is used")
+	log.Infof("[Storage] local afero storage is used")
 	afs := afero.NewBasePathFs(afero.NewOsFs(), "tmp/afero")
 	fileRepo, err = fs.NewFile(afs, conf.AssetBaseURL)
 	if err != nil {
diff --git a/server/internal/infrastructure/gcs/file.go b/server/internal/infrastructure/gcs/file.go
index 94e9c65e1d..9fa2effe04 100644
--- a/server/internal/infrastructure/gcs/file.go
+++ b/server/internal/infrastructure/gcs/file.go
@@ -427,17 +427,51 @@ func (f *fileRepo) read(ctx context.Context, filename string) (io.ReadCloser, er
 		return resp.Body, nil
 	}
 
-	reader, err := bucket.Object(filename).NewReader(ctx)
+	obj := bucket.Object(filename)
+
+	attrs, err := obj.Attrs(ctx)
+	if err != nil {
+		if errors.Is(err, storage.ErrObjectNotExist) {
+			return nil, rerror.ErrNotFound
+		}
+		log.Errorfc(ctx, "gcs: attrs err: %+v\n", err)
+		return nil, rerror.ErrInternalByWithContext(ctx, err)
+	}
+
+	reader, err := obj.Generation(attrs.Generation).NewReader(ctx)
 	if err != nil {
 		if errors.Is(err, storage.ErrObjectNotExist) {
+			if OK := f.exists(ctx, bucket, filename); OK {
+				return nil, errors.New("no read permission")
+			}
 			return nil, rerror.ErrNotFound
 		}
-		return nil, visualizer.ErrorWithCallerLogging(ctx, "gcs: read object err", rerror.ErrInternalByWithContext(ctx, err))
+		log.Errorfc(ctx, "gcs: generation read err: %+v\n", err)
+		return nil, rerror.ErrInternalByWithContext(ctx, err)
 	}
 
 	return reader, nil
 }
 
+func (f *fileRepo) exists(ctx context.Context, bucket *storage.BucketHandle, filename string) bool {
+	fmt.Printf("Checking existence: %s\n", filename)
+
+	obj := bucket.Object(filename)
+	attrs, err := obj.Attrs(ctx)
+	if err != nil {
+		if errors.Is(err, storage.ErrObjectNotExist) {
+			fmt.Printf("File does NOT exist: %s\n", filename)
+			return false
+		}
+		fmt.Printf("Error checking existence: %+v\n", err)
+		return false
+	}
+
+	fmt.Printf("OK! File exist: %s , Updated: %v (Size: %d bytes, Generation: %d)\n",
+		filename, attrs.Updated, attrs.Size, attrs.Generation)
+	return true
+}
+
 func (f *fileRepo) upload(ctx context.Context, filename string, content io.Reader) (int64, error) {
 	if filename == "" {
 		return 0, gateway.ErrInvalidFile
diff --git a/server/internal/usecase/interactor/common.go b/server/internal/usecase/interactor/common.go
index 9f5aef1d37..4f886d74b5 100644
--- a/server/internal/usecase/interactor/common.go
+++ b/server/internal/usecase/interactor/common.go
@@ -269,10 +269,10 @@ func (d ProjectDeleter) Delete(ctx context.Context, prj *project.Project, force
 }
 
 func IsCurrentHostAssets(ctx context.Context, u string) bool {
-	if strings.HasPrefix(u, "assets/") || strings.HasPrefix(u, "/assets") {
+	if strings.HasPrefix(u, "assets/") && strings.HasPrefix(u, adapter.CurrentHost(ctx)) {
 		return true
 	}
-	return strings.HasPrefix(u, adapter.CurrentHost(ctx))
+	return false
 }
 
 func ReplaceToCurrentHost(ctx context.Context, urlString string) string {