diff --git a/lib/paneron/register/raw/register.rb b/lib/paneron/register/raw/register.rb
index be9ac5d..b47fd00 100644
--- a/lib/paneron/register/raw/register.rb
+++ b/lib/paneron/register/raw/register.rb
@@ -292,7 +292,7 @@ def self.local_cache_path
             )
           else
             File.join(
-              Dir.exist?(ENV["XDG_CACHE_HOME"]) ? ENV["XDG_CACHE_HOME"] : "~/.cache",
+              Dir.exist?(ENV["XDG_CACHE_HOME"].to_s) ? ENV["XDG_CACHE_HOME"] : "~/.cache",
               "ruby-paneron-register",
             )
           end