diff --git a/fvtt-celestopol.mjs b/fvtt-celestopol.mjs
index e21e224..b0645c8 100644
--- a/fvtt-celestopol.mjs
+++ b/fvtt-celestopol.mjs
@@ -62,7 +62,7 @@ Hooks.once("init", () => {
 
   // ── Sheets: unregister core, register system sheets ─────────────────────
   foundry.applications.sheets.ActorSheetV2.unregisterSheet?.("core", "Actor", { types: ["character", "npc"] })
-  foundry.documents.collections.Actors.unregisterSheet("core", ActorSheet)
+  foundry.documents.collections.Actors.unregisterSheet("core", foundry.appv1.sheets.ActorSheet)
   foundry.documents.collections.Actors.registerSheet(SYSTEM_ID, CelestopolCharacterSheet, {
     types: ["character"],
     makeDefault: true,