diff --git a/app/controllers/admin/backups_controller.rb b/app/controllers/admin/backups_controller.rb
index 6222fc2b0..3c7855668 100644
--- a/app/controllers/admin/backups_controller.rb
+++ b/app/controllers/admin/backups_controller.rb
@@ -119,7 +119,7 @@ class Admin::BackupsController < Admin::AdminController
 
     return render status: 415, text: I18n.t("backup.backup_file_should_be_tar_gz") unless /\.(tar\.gz|t?gz)$/i =~ filename
     return render status: 415, text: I18n.t("backup.not_enough_space_on_disk")     unless has_enough_space_on_disk?(total_size)
-    return render status: 415, text: I18n.t("backup.invalid_filename") unless !!(/^[a-zA-Z0-9\.-_]+$/ =~ filename)
+    return render status: 415, text: I18n.t("backup.invalid_filename") unless !!(/^[a-zA-Z0-9\._\-]+$/ =~ filename)
 
     file               = params.fetch(:file)
     identifier         = params.fetch(:resumableIdentifier)
diff --git a/spec/controllers/admin/backups_controller_spec.rb b/spec/controllers/admin/backups_controller_spec.rb
index 092a945bc..080f4eb6c 100644
--- a/spec/controllers/admin/backups_controller_spec.rb
+++ b/spec/controllers/admin/backups_controller_spec.rb
@@ -212,7 +212,7 @@ describe Admin::BackupsController do
           described_class.any_instance.expects(:has_enough_space_on_disk?).returns(true)
 
           xhr :post, :upload_backup_chunk,
-            resumableFilename: 'test.tar.gz',
+            resumableFilename: 'test_Site-0123456789.tar.gz',
             resumableTotalSize: 1,
             resumableIdentifier: 'test',
             resumableChunkNumber: '1',