diff --git a/app/controllers/admin/backups_controller.rb b/app/controllers/admin/backups_controller.rb
index 6222fc2b088..82aebfc6c9d 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 dc44007ca3e..8ecfe105a9c 100644
--- a/spec/controllers/admin/backups_controller_spec.rb
+++ b/spec/controllers/admin/backups_controller_spec.rb
@@ -209,8 +209,8 @@ describe Admin::BackupsController do
       describe "when filename is valid" do
         it "should upload the file successfully" do
           xhr :post, :upload_backup_chunk,
-            resumableFilename: 'test.tar.gz',
-            resumableTotalSize: '1',
+            resumableFilename: 'test_Site-0123456789.tar.gz',
+            resumableTotalSize: 1,
             resumableIdentifier: 'test',
             resumableChunkNumber: '1',
             resumableChunkSize: '1',