diff --git a/src/backend/database/routes/users.ts b/src/backend/database/routes/users.ts
index 3c2303cc..11d600f6 100644
--- a/src/backend/database/routes/users.ts
+++ b/src/backend/database/routes/users.ts
@@ -18,7 +18,6 @@ import QRCode from "qrcode";
 import type { Request, Response } from "express";
 import { authLogger } from "../../utils/logger.js";
 import { AuthManager } from "../../utils/auth-manager.js";
-import { UserCrypto } from "../../utils/user-crypto.js";
 import { DataCrypto } from "../../utils/data-crypto.js";
 import { LazyFieldEncryption } from "../../utils/lazy-field-encryption.js";
 
@@ -1318,8 +1317,48 @@ router.post("/complete-reset", async (req, res) => {
       .where(eq(users.username, username));
 
     try {
-      await authManager.registerUser(userId, newPassword);
-      authManager.logoutUser(userId);
+      const hasActiveSession = authManager.isUserUnlocked(userId);
+      
+      if (hasActiveSession) {
+        const success = await authManager.resetUserPasswordWithPreservedDEK(
+          userId,
+          newPassword,
+        );
+
+        if (!success) {
+          authLogger.warn(
+            `Failed to preserve DEK during password reset for ${username}. Creating new DEK - data will be lost.`,
+            {
+              operation: "password_reset_preserve_failed",
+              userId,
+              username,
+            },
+          );
+          await authManager.registerUser(userId, newPassword);
+          authManager.logoutUser(userId);
+        } else {
+          authLogger.success(
+            `Password reset completed for user: ${username}. Data preserved using existing session.`,
+            {
+              operation: "password_reset_data_preserved",
+              userId,
+              username,
+            },
+          );
+        }
+      } else {
+        await authManager.registerUser(userId, newPassword);
+        authManager.logoutUser(userId);
+
+        authLogger.warn(
+          `Password reset completed for user: ${username}. Existing encrypted data is now inaccessible and will need to be re-entered.`,
+          {
+            operation: "password_reset_data_inaccessible",
+            userId,
+            username,
+          },
+        );
+      }
 
       await db
         .update(users)
@@ -1329,15 +1368,6 @@ router.post("/complete-reset", async (req, res) => {
           totp_backup_codes: null,
         })
         .where(eq(users.id, userId));
-
-      authLogger.warn(
-        `Password reset completed for user: ${username}. Existing encrypted data is now inaccessible and will need to be re-entered.`,
-        {
-          operation: "password_reset_data_inaccessible",
-          userId,
-          username,
-        },
-      );
     } catch (encryptionError) {
       authLogger.error(
         "Failed to re-encrypt user data after password reset",
@@ -2014,6 +2044,9 @@ router.post("/change-password", authenticateJWT, async (req, res) => {
         .set({ password_hash: newPasswordHash })
         .where(eq(users.id, userId));
 
+      const { saveMemoryDatabaseToFile } = await import("../db/index.js");
+      await saveMemoryDatabaseToFile();
+
       authLogger.success("User password changed successfully", {
         operation: "password_change_success",
         userId,
diff --git a/src/backend/utils/auth-manager.ts b/src/backend/utils/auth-manager.ts
index 541d889f..a13db6cd 100644
--- a/src/backend/utils/auth-manager.ts
+++ b/src/backend/utils/auth-manager.ts
@@ -295,6 +295,16 @@ class AuthManager {
       newPassword,
     );
   }
+
+  async resetUserPasswordWithPreservedDEK(
+    userId: string,
+    newPassword: string,
+  ): Promise<boolean> {
+    return await this.userCrypto.resetUserPasswordWithPreservedDEK(
+      userId,
+      newPassword,
+    );
+  }
 }
 
 export { AuthManager, type AuthenticationResult, type JWTPayload };
diff --git a/src/backend/utils/user-crypto.ts b/src/backend/utils/user-crypto.ts
index 73a2e39f..8e12778d 100644
--- a/src/backend/utils/user-crypto.ts
+++ b/src/backend/utils/user-crypto.ts
@@ -1,6 +1,6 @@
 import crypto from "crypto";
 import { getDb } from "../database/db/index.js";
-import { settings, users } from "../database/db/schema.js";
+import { settings } from "../database/db/schema.js";
 import { eq } from "drizzle-orm";
 import { databaseLogger } from "./logger.js";
 
@@ -263,19 +263,82 @@ class UserCrypto {
 
       const newKekSalt = await this.generateKEKSalt();
       const newKEK = this.deriveKEK(newPassword, newKekSalt);
+      
       const newEncryptedDEK = this.encryptDEK(DEK, newKEK);
 
       await this.storeKEKSalt(userId, newKekSalt);
       await this.storeEncryptedDEK(userId, newEncryptedDEK);
 
+      const { saveMemoryDatabaseToFile } = await import("../database/db/index.js");
+      await saveMemoryDatabaseToFile();
+
       oldKEK.fill(0);
       newKEK.fill(0);
-      DEK.fill(0);
 
-      this.logoutUser(userId);
+      const dekCopy = Buffer.from(DEK);
+
+      const now = Date.now();
+      const oldSession = this.userSessions.get(userId);
+      if (oldSession) {
+        oldSession.dataKey.fill(0);
+      }
+      
+      this.userSessions.set(userId, {
+        dataKey: dekCopy,
+        lastActivity: now,
+        expiresAt: now + UserCrypto.SESSION_DURATION,
+      });
+
+      DEK.fill(0);
 
       return true;
     } catch (error) {
+      databaseLogger.error("Password change failed", error, {
+        operation: "password_change_error",
+        userId,
+        error: error instanceof Error ? error.message : "Unknown error",
+      });
+      return false;
+    }
+  }
+
+  async resetUserPasswordWithPreservedDEK(
+    userId: string,
+    newPassword: string,
+  ): Promise<boolean> {
+    try {
+      const existingDEK = this.getUserDataKey(userId);
+      if (!existingDEK) {
+        return false;
+      }
+
+      const newKekSalt = await this.generateKEKSalt();
+      const newKEK = this.deriveKEK(newPassword, newKekSalt);
+
+      const newEncryptedDEK = this.encryptDEK(existingDEK, newKEK);
+
+      await this.storeKEKSalt(userId, newKekSalt);
+      await this.storeEncryptedDEK(userId, newEncryptedDEK);
+
+      const { saveMemoryDatabaseToFile } = await import(
+        "../database/db/index.js"
+      );
+      await saveMemoryDatabaseToFile();
+
+      newKEK.fill(0);
+
+      const session = this.userSessions.get(userId);
+      if (session) {
+        session.lastActivity = Date.now();
+      }
+
+      return true;
+    } catch (error) {
+      databaseLogger.error("Password reset with preserved DEK failed", error, {
+        operation: "password_reset_preserve_error",
+        userId,
+        error: error instanceof Error ? error.message : "Unknown error",
+      });
       return false;
     }
   }