diff --git a/README.md b/README.md
index d2e26ca..42f3e1a 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,3 @@
-
 # Usefull commands
 
 ## Configure
@@ -39,6 +38,11 @@ Clean up all useless store from old profiles
 sudo nix store gc --debug
 ```
 
+error: cached failure of attribute 'nixosConfigurations.perso-desktop.config.system.build.toplevel'
+```bash
+sudo rm -fr /root/.cache/nix/
+```
+
 # Usefull links
 
 - https://api.github.com/rate_limit