diff --git a/apps/isa-app/src/app/store/root-state.service.ts b/apps/isa-app/src/app/store/root-state.service.ts
index 59e437a85..32c99dc3d 100644
--- a/apps/isa-app/src/app/store/root-state.service.ts
+++ b/apps/isa-app/src/app/store/root-state.service.ts
@@ -1,18 +1,18 @@
-import { Injectable } from '@angular/core';
-import { Logger, LogLevel } from '@core/logger';
-import { Store } from '@ngrx/store';
-import { debounceTime, switchMap, takeUntil } from 'rxjs/operators';
-import { RootState } from './root.state';
-import packageInfo from 'packageJson';
-import { environment } from '../../environments/environment';
-import { Subject } from 'rxjs';
-import { AuthService } from '@core/auth';
-import { injectStorage, UserStorageProvider } from '@isa/core/storage';
-import { isEqual } from 'lodash';
+import { Injectable } from "@angular/core";
+import { Logger, LogLevel } from "@core/logger";
+import { Store } from "@ngrx/store";
+import { debounceTime, switchMap, takeUntil } from "rxjs/operators";
+import { RootState } from "./root.state";
+import packageInfo from "packageJson";
+import { environment } from "../../environments/environment";
+import { Subject } from "rxjs";
+import { AuthService } from "@core/auth";
+import { injectStorage, UserStorageProvider } from "@isa/core/storage";
+import { isEqual } from "lodash";
 
-@Injectable({ providedIn: 'root' })
+@Injectable({ providedIn: "root" })
 export class RootStateService {
-  static LOCAL_STORAGE_KEY = 'ISA_APP_INITIALSTATE';
+  static LOCAL_STORAGE_KEY = "ISA_APP_INITIALSTATE";
 
   #storage = injectStorage(UserStorageProvider);
 
@@ -29,14 +29,17 @@ export class RootStateService {
       );
     }
 
-    window['clearUserState'] = () => {
+    window["clearUserState"] = () => {
       this.clear();
     };
   }
 
   async init() {
     await this.load();
-    this._store.dispatch({ type: 'HYDRATE', payload: RootStateService.LoadFromLocalStorage() });
+    this._store.dispatch({
+      type: "HYDRATE",
+      payload: RootStateService.LoadFromLocalStorage(),
+    });
     this.initSave();
   }
 
@@ -50,14 +53,10 @@ export class RootStateService {
           const data = {
             ...state,
             version: packageInfo.version,
-            sub: this._authService.getClaimByKey('sub'),
+            sub: this._authService.getClaimByKey("sub"),
           };
           RootStateService.SaveToLocalStorageRaw(JSON.stringify(data));
-          return this.#storage.set('state', {
-            ...state,
-            version: packageInfo.version,
-            sub: this._authService.getClaimByKey('sub'),
-          });
+          return this.#storage.set("state", data);
         }),
       )
       .subscribe();
@@ -68,7 +67,7 @@ export class RootStateService {
    */
   async load(): Promise<boolean> {
     try {
-      const res = await this.#storage.get('state');
+      const res = await this.#storage.get("state");
 
       const storageContent = RootStateService.LoadFromLocalStorageRaw();
 
@@ -88,7 +87,7 @@ export class RootStateService {
   async clear() {
     try {
       this._cancelSave.next();
-      await this.#storage.clear('state');
+      await this.#storage.clear("state");
       await new Promise((resolve) => setTimeout(resolve, 100));
       RootStateService.RemoveFromLocalStorage();
       await new Promise((resolve) => setTimeout(resolve, 100));
@@ -112,7 +111,7 @@ export class RootStateService {
       try {
         return JSON.parse(raw);
       } catch (error) {
-        console.error('Error parsing local storage:', error);
+        console.error("Error parsing local storage:", error);
         this.RemoveFromLocalStorage();
       }
     }
diff --git a/libs/core/storage/src/lib/user.storage-provider.ts b/libs/core/storage/src/lib/user.storage-provider.ts
index 04f330e05..9dc3be7ed 100644
--- a/libs/core/storage/src/lib/user.storage-provider.ts
+++ b/libs/core/storage/src/lib/user.storage-provider.ts
@@ -1,27 +1,42 @@
-import { inject, Injectable } from '@angular/core';
-import { StorageProvider } from './storage-provider';
-import { UserStateService } from '@generated/swagger/isa-api';
-import { firstValueFrom, map, shareReplay } from 'rxjs';
+import { inject, Injectable } from "@angular/core";
+import { StorageProvider } from "./storage-provider";
+import { UserStateService } from "@generated/swagger/isa-api";
+import { catchError, firstValueFrom, map, of } from "rxjs";
+import { isEmpty } from "lodash";
 
-@Injectable({ providedIn: 'root' })
+@Injectable({ providedIn: "root" })
 export class UserStorageProvider implements StorageProvider {
   #userStateService = inject(UserStateService);
 
   private state$ = this.#userStateService.UserStateGetUserState().pipe(
     map((res) => {
-      if (res.result?.content) {
+      if (res?.result?.content) {
         return JSON.parse(res.result.content);
       }
       return {};
     }),
-    shareReplay(1),
+    catchError((err) => {
+      console.warn(
+        "No UserStateGetUserState found, returning empty object:",
+        err,
+      );
+      return of({}); // Return empty state fallback
+    }),
+    // shareReplay(1), #5249, #5270 Würde beim Fehlerfall den fehlerhaften Zustand behalten
+    // Aktuell wird nun jedes mal 2 mal der UserState aufgerufen (GET + POST)
+    // Damit bei der set Funktion immer der aktuelle Zustand verwendet wird
   );
 
-  async set(key: string, value: unknown): Promise<void> {
+  async set(key: string, value: Record<string, unknown>): Promise<void> {
     const current = await firstValueFrom(this.state$);
-    firstValueFrom(
+    const content =
+      current && !isEmpty(current)
+        ? { ...current, [key]: value }
+        : { [key]: value };
+
+    await firstValueFrom(
       this.#userStateService.UserStateSetUserState({
-        content: JSON.stringify({ ...current, [key]: value }),
+        content: JSON.stringify(content),
       }),
     );
   }
@@ -32,7 +47,6 @@ export class UserStorageProvider implements StorageProvider {
   }
 
   async clear(key: string): Promise<void> {
-     
     const current = await firstValueFrom(this.state$);
     delete current[key];
     firstValueFrom(this.#userStateService.UserStateResetUserState());