diff --git a/src/components/theme-customizer/index.tsx b/src/components/theme-customizer/index.tsx
index c719243..2e1482e 100644
--- a/src/components/theme-customizer/index.tsx
+++ b/src/components/theme-customizer/index.tsx
@@ -9,6 +9,7 @@ import { useThemeManager } from '@/hooks/use-theme-manager'
 import { useTheme } from '@/hooks/use-theme'
 import { useSidebarConfig } from '@/contexts/sidebar-context'
 import { tweakcnThemes } from '@/config/theme-data'
+import { toast } from 'sonner'
 import { saveUserPrefsAction } from '@/lib/appwrite/user-prefs-actions'
 import type { UserPrefs as ThemePrefs } from '@/lib/appwrite/user-prefs-actions'
 import { getLocalThemePrefs, saveLocalThemePrefs } from '@/lib/local-theme-prefs'
@@ -58,6 +59,12 @@ export function ThemeCustomizer({ open, onOpenChange, initialPrefs }: ThemeCusto
     })
   }, [sidebarConfig.variant, sidebarConfig.collapsible, sidebarConfig.side])
 
+  const savePrefs = (update: Parameters<typeof saveUserPrefsAction>[0]) => {
+    saveUserPrefsAction(update).then((res) => {
+      if (!res.ok) toast.error("Tercihler kaydedilemedi: " + res.error)
+    })
+  }
+
   const handleReset = () => {
     setSelectedTheme("default")
     setSelectedTweakcnTheme("")
@@ -68,7 +75,7 @@ export function ThemeCustomizer({ open, onOpenChange, initialPrefs }: ThemeCusto
     applyRadius("0.5rem")
     updateSidebarConfig({ variant: "inset", collapsible: "offcanvas", side: "left" })
     saveLocalThemePrefs({ colorTheme: "default", tweakcnTheme: "", radius: "0.5rem", sidebarVariant: "inset", sidebarCollapsible: "offcanvas", sidebarSide: "left" })
-    void saveUserPrefsAction({ colorTheme: "default", tweakcnTheme: "", radius: "0.5rem", sidebarVariant: "inset", sidebarCollapsible: "offcanvas", sidebarSide: "left" })
+    savePrefs({ colorTheme: "default", tweakcnTheme: "", radius: "0.5rem", sidebarVariant: "inset", sidebarCollapsible: "offcanvas", sidebarSide: "left" })
   }
 
   const handleImport = (themeData: ImportedTheme) => {
@@ -165,20 +172,20 @@ export function ThemeCustomizer({ open, onOpenChange, initialPrefs }: ThemeCusto
                     setSelectedTheme(value)
                     setSelectedTweakcnTheme("")
                     saveLocalThemePrefs({ colorTheme: value, tweakcnTheme: "" })
-                    void saveUserPrefsAction({ colorTheme: value, tweakcnTheme: "" })
+                    savePrefs({ colorTheme: value, tweakcnTheme: "" })
                   }}
                   selectedTweakcnTheme={selectedTweakcnTheme}
                   setSelectedTweakcnTheme={(value) => {
                     setSelectedTweakcnTheme(value)
                     setSelectedTheme("")
                     saveLocalThemePrefs({ tweakcnTheme: value, colorTheme: "" })
-                    void saveUserPrefsAction({ tweakcnTheme: value, colorTheme: "" })
+                    savePrefs({ tweakcnTheme: value, colorTheme: "" })
                   }}
                   selectedRadius={selectedRadius}
                   setSelectedRadius={(value) => {
                     setSelectedRadius(value)
                     saveLocalThemePrefs({ radius: value })
-                    void saveUserPrefsAction({ radius: value })
+                    savePrefs({ radius: value })
                   }}
                   setImportedTheme={setImportedTheme}
                   onImportClick={handleImportClick}
diff --git a/src/lib/appwrite/user-prefs-actions.ts b/src/lib/appwrite/user-prefs-actions.ts
index e3eb364..d10f4c8 100644
--- a/src/lib/appwrite/user-prefs-actions.ts
+++ b/src/lib/appwrite/user-prefs-actions.ts
@@ -30,11 +30,12 @@ export async function getUserPrefs(): Promise<UserPrefs> {
     if (result.rows.length === 0) return {};
 
     const row = result.rows[0] as Record<string, unknown>;
+    const str = (v: unknown) => (v && typeof v === "string" ? v : undefined);
     return {
       theme: (row.theme as UserPrefs["theme"]) ?? undefined,
-      colorTheme: (row.colorTheme as string) ?? undefined,
-      tweakcnTheme: (row.tweakcnTheme as string) ?? undefined,
-      radius: (row.radius as string) ?? undefined,
+      colorTheme: str(row.colorTheme),
+      tweakcnTheme: str(row.tweakcnTheme),
+      radius: str(row.radius),
       sidebarVariant: (row.sidebarVariant as UserPrefs["sidebarVariant"]) ?? undefined,
       sidebarCollapsible: (row.sidebarCollapsible as UserPrefs["sidebarCollapsible"]) ?? undefined,
       sidebarSide: (row.sidebarSide as UserPrefs["sidebarSide"]) ?? undefined,
@@ -44,18 +45,21 @@ export async function getUserPrefs(): Promise<UserPrefs> {
   }
 }
 
-export async function saveUserPrefsAction(update: Partial<UserPrefs>): Promise<void> {
+export async function saveUserPrefsAction(
+  update: Partial<UserPrefs>,
+): Promise<{ ok: boolean; error?: string }> {
   try {
     const { account } = await createSessionClient();
     const user = await account.get();
     const { tablesDB } = createAdminClient();
 
-    // Sadece tanımlı (undefined olmayan) alanları yaz
+    // undefined → skip, "" → null (Appwrite rejects empty strings on nullable attrs)
     const clean: Record<string, unknown> = {};
     for (const [k, v] of Object.entries(update)) {
-      if (v !== undefined) clean[k] = v;
+      if (v === undefined) continue;
+      clean[k] = v === "" ? null : v;
     }
-    if (Object.keys(clean).length === 0) return;
+    if (Object.keys(clean).length === 0) return { ok: true };
 
     const existing = await tablesDB.listRows({
       databaseId: DATABASE_ID,
@@ -85,7 +89,11 @@ export async function saveUserPrefsAction(update: Partial<UserPrefs>): Promise<v
         clean,
       );
     }
-  } catch {
-    // best-effort
+
+    return { ok: true };
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : String(err);
+    console.error("[saveUserPrefsAction]", msg);
+    return { ok: false, error: msg };
   }
 }