diff --git a/.github/workflows/electron.yml b/.github/workflows/electron.yml
index 62bf5769..bd1a5b4c 100644
--- a/.github/workflows/electron.yml
+++ b/.github/workflows/electron.yml
@@ -746,7 +746,6 @@ jobs:
           mkdir -p homebrew-submission/Casks/t
 
           cp homebrew/termix.rb homebrew-submission/Casks/t/termix.rb
-          cp homebrew/README.md homebrew-submission/
 
           sed -i '' "s/VERSION_PLACEHOLDER/$VERSION/g" homebrew-submission/Casks/t/termix.rb
           sed -i '' "s/CHECKSUM_PLACEHOLDER/$CHECKSUM/g" homebrew-submission/Casks/t/termix.rb
diff --git a/src/backend/database/db/index.ts b/src/backend/database/db/index.ts
index 7b3b6138..8310ed6c 100644
--- a/src/backend/database/db/index.ts
+++ b/src/backend/database/db/index.ts
@@ -95,6 +95,32 @@ async function initializeDatabaseAsync(): Promise<void> {
         databaseKeyLength: process.env.DATABASE_KEY?.length || 0,
       });
 
+      try {
+        databaseLogger.info(
+          "Generating diagnostic information for database encryption failure",
+          {
+            operation: "db_encryption_diagnostic",
+          },
+        );
+        const diagnosticInfo =
+          DatabaseFileEncryption.getDiagnosticInfo(encryptedDbPath);
+        databaseLogger.error(
+          "Database encryption diagnostic completed - check logs above for details",
+          null,
+          {
+            operation: "db_encryption_diagnostic_completed",
+            filesConsistent: diagnosticInfo.validation.filesConsistent,
+            sizeMismatch: diagnosticInfo.validation.sizeMismatch,
+          },
+        );
+      } catch (diagError) {
+        databaseLogger.warn("Failed to generate diagnostic information", {
+          operation: "db_diagnostic_failed",
+          error:
+            diagError instanceof Error ? diagError.message : "Unknown error",
+        });
+      }
+
       throw new Error(
         `Database decryption failed: ${error instanceof Error ? error.message : "Unknown error"}. This prevents data loss.`,
       );
diff --git a/src/backend/utils/database-file-encryption.ts b/src/backend/utils/database-file-encryption.ts
index 002464b0..7bbb406b 100644
--- a/src/backend/utils/database-file-encryption.ts
+++ b/src/backend/utils/database-file-encryption.ts
@@ -12,6 +12,7 @@ interface EncryptedFileMetadata {
   algorithm: string;
   keySource?: string;
   salt?: string;
+  dataSize?: number;
 }
 
 class DatabaseFileEncryption {
@@ -25,6 +26,10 @@ class DatabaseFileEncryption {
     buffer: Buffer,
     targetPath: string,
   ): Promise<string> {
+    const tmpPath = `${targetPath}.tmp-${Date.now()}-${process.pid}`;
+    const tmpMetadataPath = `${tmpPath}${this.METADATA_FILE_SUFFIX}`;
+    const metadataPath = `${targetPath}${this.METADATA_FILE_SUFFIX}`;
+
     try {
       const key = await this.systemCrypto.getDatabaseKey();
 
@@ -38,6 +43,12 @@ class DatabaseFileEncryption {
       const encrypted = Buffer.concat([cipher.update(buffer), cipher.final()]);
       const tag = cipher.getAuthTag();
 
+      const keyFingerprint = crypto
+        .createHash("sha256")
+        .update(key)
+        .digest("hex")
+        .substring(0, 16);
+
       const metadata: EncryptedFileMetadata = {
         iv: iv.toString("hex"),
         tag: tag.toString("hex"),
@@ -45,14 +56,35 @@ class DatabaseFileEncryption {
         fingerprint: "termix-v2-systemcrypto",
         algorithm: this.ALGORITHM,
         keySource: "SystemCrypto",
+        dataSize: encrypted.length,
       };
 
-      const metadataPath = `${targetPath}${this.METADATA_FILE_SUFFIX}`;
-      fs.writeFileSync(targetPath, encrypted);
-      fs.writeFileSync(metadataPath, JSON.stringify(metadata, null, 2));
+      fs.writeFileSync(tmpPath, encrypted);
+      fs.writeFileSync(tmpMetadataPath, JSON.stringify(metadata, null, 2));
+
+      fs.renameSync(tmpPath, targetPath);
+      fs.renameSync(tmpMetadataPath, metadataPath);
 
       return targetPath;
     } catch (error) {
+      try {
+        if (fs.existsSync(tmpPath)) {
+          fs.unlinkSync(tmpPath);
+        }
+        if (fs.existsSync(tmpMetadataPath)) {
+          fs.unlinkSync(tmpMetadataPath);
+        }
+      } catch (cleanupError) {
+        databaseLogger.warn("Failed to cleanup temporary files", {
+          operation: "temp_file_cleanup_failed",
+          tmpPath,
+          error:
+            cleanupError instanceof Error
+              ? cleanupError.message
+              : "Unknown error",
+        });
+      }
+
       databaseLogger.error("Failed to encrypt database buffer", error, {
         operation: "database_buffer_encryption_failed",
         targetPath,
@@ -74,6 +106,8 @@ class DatabaseFileEncryption {
     const encryptedPath =
       targetPath || `${sourcePath}${this.ENCRYPTED_FILE_SUFFIX}`;
     const metadataPath = `${encryptedPath}${this.METADATA_FILE_SUFFIX}`;
+    const tmpPath = `${encryptedPath}.tmp-${Date.now()}-${process.pid}`;
+    const tmpMetadataPath = `${tmpPath}${this.METADATA_FILE_SUFFIX}`;
 
     try {
       const sourceData = fs.readFileSync(sourcePath);
@@ -93,6 +127,12 @@ class DatabaseFileEncryption {
       ]);
       const tag = cipher.getAuthTag();
 
+      const keyFingerprint = crypto
+        .createHash("sha256")
+        .update(key)
+        .digest("hex")
+        .substring(0, 16);
+
       const metadata: EncryptedFileMetadata = {
         iv: iv.toString("hex"),
         tag: tag.toString("hex"),
@@ -100,10 +140,14 @@ class DatabaseFileEncryption {
         fingerprint: "termix-v2-systemcrypto",
         algorithm: this.ALGORITHM,
         keySource: "SystemCrypto",
+        dataSize: encrypted.length,
       };
 
-      fs.writeFileSync(encryptedPath, encrypted);
-      fs.writeFileSync(metadataPath, JSON.stringify(metadata, null, 2));
+      fs.writeFileSync(tmpPath, encrypted);
+      fs.writeFileSync(tmpMetadataPath, JSON.stringify(metadata, null, 2));
+
+      fs.renameSync(tmpPath, encryptedPath);
+      fs.renameSync(tmpMetadataPath, metadataPath);
 
       databaseLogger.info("Database file encrypted successfully", {
         operation: "database_file_encryption",
@@ -111,11 +155,30 @@ class DatabaseFileEncryption {
         encryptedPath,
         fileSize: sourceData.length,
         encryptedSize: encrypted.length,
+        keyFingerprint,
         fingerprintPrefix: metadata.fingerprint,
       });
 
       return encryptedPath;
     } catch (error) {
+      try {
+        if (fs.existsSync(tmpPath)) {
+          fs.unlinkSync(tmpPath);
+        }
+        if (fs.existsSync(tmpMetadataPath)) {
+          fs.unlinkSync(tmpMetadataPath);
+        }
+      } catch (cleanupError) {
+        databaseLogger.warn("Failed to cleanup temporary files", {
+          operation: "temp_file_cleanup_failed",
+          tmpPath,
+          error:
+            cleanupError instanceof Error
+              ? cleanupError.message
+              : "Unknown error",
+        });
+      }
+
       databaseLogger.error("Failed to encrypt database file", error, {
         operation: "database_file_encryption_failed",
         sourcePath,
@@ -140,11 +203,34 @@ class DatabaseFileEncryption {
     }
 
     try {
+      const dataFileStats = fs.statSync(encryptedPath);
+      const metaFileStats = fs.statSync(metadataPath);
+
       const metadataContent = fs.readFileSync(metadataPath, "utf8");
       const metadata: EncryptedFileMetadata = JSON.parse(metadataContent);
 
       const encryptedData = fs.readFileSync(encryptedPath);
 
+      if (metadata.dataSize !== undefined && encryptedData.length !== metadata.dataSize) {
+        databaseLogger.error(
+          "Encrypted file size mismatch - possible corrupted write or mismatched metadata",
+          null,
+          {
+            operation: "database_file_size_mismatch",
+            encryptedPath,
+            actualSize: encryptedData.length,
+            expectedSize: metadata.dataSize,
+            difference: encryptedData.length - metadata.dataSize,
+            dataFileMtime: dataFileStats.mtime.toISOString(),
+            metaFileMtime: metaFileStats.mtime.toISOString(),
+          },
+        );
+        throw new Error(
+          `Encrypted file size mismatch: expected ${metadata.dataSize} bytes but got ${encryptedData.length} bytes. ` +
+            `This indicates corrupted files or interrupted write operation.`,
+        );
+      }
+
       let key: Buffer;
       if (metadata.version === "v2") {
         key = await this.systemCrypto.getDatabaseKey();
@@ -167,6 +253,12 @@ class DatabaseFileEncryption {
         throw new Error(`Unsupported encryption version: ${metadata.version}`);
       }
 
+      const keyFingerprint = crypto
+        .createHash("sha256")
+        .update(key)
+        .digest("hex")
+        .substring(0, 16);
+
       const decipher = crypto.createDecipheriv(
         metadata.algorithm,
         key,
@@ -181,13 +273,64 @@ class DatabaseFileEncryption {
 
       return decryptedBuffer;
     } catch (error) {
+      const errorMessage =
+        error instanceof Error ? error.message : "Unknown error";
+      const isAuthError =
+        errorMessage.includes("Unsupported state") ||
+        errorMessage.includes("authenticate data") ||
+        errorMessage.includes("auth");
+
+      if (isAuthError) {
+        const dataDir = process.env.DATA_DIR || "./db/data";
+        const envPath = path.join(dataDir, ".env");
+
+        let envFileExists = false;
+        let envFileReadable = false;
+        try {
+          envFileExists = fs.existsSync(envPath);
+          if (envFileExists) {
+            fs.accessSync(envPath, fs.constants.R_OK);
+            envFileReadable = true;
+          }
+        } catch {}
+
+        databaseLogger.error(
+          "Database decryption authentication failed - possible causes: wrong DATABASE_KEY, corrupted files, or interrupted write",
+          error,
+          {
+            operation: "database_buffer_decryption_auth_failed",
+            encryptedPath,
+            metadataPath,
+            dataDir,
+            envPath,
+            envFileExists,
+            envFileReadable,
+            hasEnvKey: !!process.env.DATABASE_KEY,
+            envKeyLength: process.env.DATABASE_KEY?.length || 0,
+            suggestion:
+              "Check if DATABASE_KEY in .env matches the key used for encryption",
+          },
+        );
+        throw new Error(
+          `Database decryption authentication failed. This usually means:\n` +
+            `1. DATABASE_KEY has changed or is missing from ${dataDir}/.env\n` +
+            `2. Encrypted file was corrupted during write (system crash/restart)\n` +
+            `3. Metadata file does not match encrypted data\n` +
+            `\nDebug info:\n` +
+            `- DATA_DIR: ${dataDir}\n` +
+            `- .env file exists: ${envFileExists}\n` +
+            `- .env file readable: ${envFileReadable}\n` +
+            `- DATABASE_KEY in environment: ${!!process.env.DATABASE_KEY}\n` +
+            `Original error: ${errorMessage}`,
+        );
+      }
+
       databaseLogger.error("Failed to decrypt database to buffer", error, {
         operation: "database_buffer_decryption_failed",
         encryptedPath,
+        errorMessage,
       });
-      throw new Error(
-        `Database buffer decryption failed: ${error instanceof Error ? error.message : "Unknown error"}`,
-      );
+      throw new Error(`Database buffer decryption failed: ${errorMessage}`);
     }
   }
 
@@ -215,6 +358,23 @@ class DatabaseFileEncryption {
 
       const encryptedData = fs.readFileSync(encryptedPath);
 
+      if (metadata.dataSize !== undefined && encryptedData.length !== metadata.dataSize) {
+        databaseLogger.error(
+          "Encrypted file size mismatch - possible corrupted write or mismatched metadata",
+          null,
+          {
+            operation: "database_file_size_mismatch",
+            encryptedPath,
+            actualSize: encryptedData.length,
+            expectedSize: metadata.dataSize,
+          },
+        );
+        throw new Error(
+          `Encrypted file size mismatch: expected ${metadata.dataSize} bytes but got ${encryptedData.length} bytes. ` +
+            `This indicates corrupted files or interrupted write operation.`,
+        );
+      }
+
       let key: Buffer;
       if (metadata.version === "v2") {
         key = await this.systemCrypto.getDatabaseKey();
@@ -322,6 +482,125 @@ class DatabaseFileEncryption {
     }
   }
 
+  static getDiagnosticInfo(encryptedPath: string): {
+    dataFile: {
+      exists: boolean;
+      size?: number;
+      mtime?: string;
+      readable?: boolean;
+    };
+    metadataFile: {
+      exists: boolean;
+      size?: number;
+      mtime?: string;
+      readable?: boolean;
+      content?: EncryptedFileMetadata;
+    };
+    environment: {
+      dataDir: string;
+      envPath: string;
+      envFileExists: boolean;
+      envFileReadable: boolean;
+      hasEnvKey: boolean;
+      envKeyLength: number;
+    };
+    validation: {
+      filesConsistent: boolean;
+      sizeMismatch?: boolean;
+      expectedSize?: number;
+      actualSize?: number;
+    };
+  } {
+    const metadataPath = `${encryptedPath}${this.METADATA_FILE_SUFFIX}`;
+    const dataDir = process.env.DATA_DIR || "./db/data";
+    const envPath = path.join(dataDir, ".env");
+
+    const result: ReturnType<typeof this.getDiagnosticInfo> = {
+      dataFile: { exists: false },
+      metadataFile: { exists: false },
+      environment: {
+        dataDir,
+        envPath,
+        envFileExists: false,
+        envFileReadable: false,
+        hasEnvKey: !!process.env.DATABASE_KEY,
+        envKeyLength: process.env.DATABASE_KEY?.length || 0,
+      },
+      validation: {
+        filesConsistent: false,
+      },
+    };
+
+    try {
+      result.dataFile.exists = fs.existsSync(encryptedPath);
+      if (result.dataFile.exists) {
+        try {
+          fs.accessSync(encryptedPath, fs.constants.R_OK);
+          result.dataFile.readable = true;
+          const stats = fs.statSync(encryptedPath);
+          result.dataFile.size = stats.size;
+          result.dataFile.mtime = stats.mtime.toISOString();
+        } catch {
+          result.dataFile.readable = false;
+        }
+      }
+
+      result.metadataFile.exists = fs.existsSync(metadataPath);
+      if (result.metadataFile.exists) {
+        try {
+          fs.accessSync(metadataPath, fs.constants.R_OK);
+          result.metadataFile.readable = true;
+          const stats = fs.statSync(metadataPath);
+          result.metadataFile.size = stats.size;
+          result.metadataFile.mtime = stats.mtime.toISOString();
+
+          const content = fs.readFileSync(metadataPath, "utf8");
+          result.metadataFile.content = JSON.parse(content);
+        } catch {
+          result.metadataFile.readable = false;
+        }
+      }
+
+      result.environment.envFileExists = fs.existsSync(envPath);
+      if (result.environment.envFileExists) {
+        try {
+          fs.accessSync(envPath, fs.constants.R_OK);
+          result.environment.envFileReadable = true;
+        } catch {}
+      }
+
+      if (
+        result.dataFile.exists &&
+        result.metadataFile.exists &&
+        result.metadataFile.content
+      ) {
+        result.validation.filesConsistent = true;
+
+        if (result.metadataFile.content.dataSize !== undefined) {
+          result.validation.expectedSize = result.metadataFile.content.dataSize;
+          result.validation.actualSize = result.dataFile.size;
+          result.validation.sizeMismatch =
+            result.metadataFile.content.dataSize !== result.dataFile.size;
+          if (result.validation.sizeMismatch) {
+            result.validation.filesConsistent = false;
+          }
+        }
+      }
+    } catch (error) {
+      databaseLogger.error("Failed to generate diagnostic info", error, {
+        operation: "diagnostic_info_failed",
+        encryptedPath,
+      });
+    }
+
+    databaseLogger.info("Database encryption diagnostic info", {
+      operation: "diagnostic_info_generated",
+      ...result,
+    });
+
+    return result;
+  }
+
   static async createEncryptedBackup(
     databasePath: string,
     backupDir: string,
diff --git a/src/backend/utils/system-crypto.ts b/src/backend/utils/system-crypto.ts
index bd6aa727..156d0b33 100644
--- a/src/backend/utils/system-crypto.ts
+++ b/src/backend/utils/system-crypto.ts
@@ -51,17 +51,8 @@ class SystemCrypto {
             },
           );
         }
-      } catch (fileError) {
-        databaseLogger.warn("Failed to read .env file for JWT secret", {
-          operation: "jwt_init_file_read_failed",
-          error:
-            fileError instanceof Error ? fileError.message : "Unknown error",
-        });
-      }
+      } catch (fileError) {}
 
-      databaseLogger.warn("Generating new JWT secret", {
-        operation: "jwt_generating_new_secret",
-      });
       await this.generateAndGuideUser();
     } catch (error) {
       databaseLogger.error("Failed to initialize JWT secret", error, {
@@ -80,29 +71,44 @@ class SystemCrypto {
 
   async initializeDatabaseKey(): Promise<void> {
     try {
+      const dataDir = process.env.DATA_DIR || "./db/data";
+      const envPath = path.join(dataDir, ".env");
+
       const envKey = process.env.DATABASE_KEY;
       if (envKey && envKey.length >= 64) {
         this.databaseKey = Buffer.from(envKey, "hex");
+        const keyFingerprint = crypto
+          .createHash("sha256")
+          .update(this.databaseKey)
+          .digest("hex")
+          .substring(0, 16);
+
         return;
       }
 
-      const dataDir = process.env.DATA_DIR || "./db/data";
-      const envPath = path.join(dataDir, ".env");
-
       try {
         const envContent = await fs.readFile(envPath, "utf8");
         const dbKeyMatch = envContent.match(/^DATABASE_KEY=(.+)$/m);
         if (dbKeyMatch && dbKeyMatch[1] && dbKeyMatch[1].length >= 64) {
           this.databaseKey = Buffer.from(dbKeyMatch[1], "hex");
           process.env.DATABASE_KEY = dbKeyMatch[1];
+
+          const keyFingerprint = crypto
+            .createHash("sha256")
+            .update(this.databaseKey)
+            .digest("hex")
+            .substring(0, 16);
+
           return;
+        } else {
         }
-      } catch {}
+      } catch (fileError) {}
 
       await this.generateAndGuideDatabaseKey();
     } catch (error) {
       databaseLogger.error("Failed to initialize database key", error, {
         operation: "db_key_init_failed",
+        dataDir: process.env.DATA_DIR || "./db/data",
       });
       throw new Error("Database key initialization failed");
     }
diff --git a/src/ui/desktop/authentication/Auth.tsx b/src/ui/desktop/authentication/Auth.tsx
index fb894adc..997d712b 100644
--- a/src/ui/desktop/authentication/Auth.tsx
+++ b/src/ui/desktop/authentication/Auth.tsx
@@ -24,11 +24,20 @@ import {
   verifyTOTPLogin,
   getServerConfig,
   isElectron,
-  logoutUser,
 } from "../../main-axios.ts";
 import { ElectronServerConfig as ServerConfigComponent } from "@/ui/desktop/authentication/ElectronServerConfig.tsx";
 import { ElectronLoginForm } from "@/ui/desktop/authentication/ElectronLoginForm.tsx";
 
+function getCookie(name: string): string | undefined {
+  const value = `; ${document.cookie}`;
+  const parts = value.split(`; ${name}=`);
+  if (parts.length === 2) return parts.pop()?.split(";").shift();
+}
+
+interface ExtendedWindow extends Window {
+  IS_ELECTRON_WEBVIEW?: boolean;
+}
+
 interface AuthProps extends React.ComponentProps<"div"> {
   setLoggedIn: (loggedIn: boolean) => void;
   setIsAdmin: (isAdmin: boolean) => void;
@@ -37,7 +46,6 @@ interface AuthProps extends React.ComponentProps<"div"> {
   loggedIn: boolean;
   authLoading: boolean;
   setDbError: (error: string | null) => void;
-  dbError?: string | null;
   onAuthSuccess: (authData: {
     isAdmin: boolean;
     username: string | null;
@@ -54,21 +62,20 @@ export function Auth({
   loggedIn,
   authLoading,
   setDbError,
-  dbError,
   onAuthSuccess,
   ...props
 }: AuthProps) {
   const { t } = useTranslation();
 
   const isInElectronWebView = () => {
-    if ((window as any).IS_ELECTRON_WEBVIEW) {
+    if ((window as ExtendedWindow).IS_ELECTRON_WEBVIEW) {
       return true;
     }
     try {
       if (window.self !== window.top) {
         return true;
       }
-    } catch (e) {
+    } catch (_e) {
       return false;
     }
     return false;
@@ -126,7 +133,7 @@ export function Auth({
         userId: meRes.userId || null,
       });
       toast.success(t("messages.loginSuccess"));
-    } catch (err) {
+    } catch (_err) {
       toast.error(t("errors.failedUserInfo"));
     }
   }, [
@@ -206,7 +213,7 @@ export function Auth({
       .finally(() => {
         setDbHealthChecking(false);
       });
-  }, [setDbError, firstUserToastShown, showServerConfig]);
+  }, [setDbError, firstUserToastShown, showServerConfig, t]);
 
   useEffect(() => {
     if (!registrationAllowed && !internalLoggedIn) {
@@ -282,9 +289,9 @@ export function Auth({
           );
           setWebviewAuthSuccess(true);
           setTimeout(() => window.location.reload(), 100);
-          setLoading(false);
-          return;
-        } catch (e) {}
+        } catch (e) {
+          console.error("Error posting auth success message:", e);
+        }
       }
 
       const [meRes] = await Promise.all([getUserInfo()]);
@@ -461,7 +468,9 @@ export function Auth({
           setTimeout(() => window.location.reload(), 100);
           setTotpLoading(false);
           return;
-        } catch (e) {}
+        } catch (e) {
+          console.error("Error posting auth success message:", e);
+        }
       }
 
       setInternalLoggedIn(true);
@@ -569,7 +578,9 @@ export function Auth({
                 setTimeout(() => window.location.reload(), 100);
                 setOidcLoading(false);
                 return;
-              } catch (e) {}
+              } catch (e) {
+                console.error("Error posting auth success message:", e);
+              }
             }
           }
 
@@ -607,7 +618,16 @@ export function Auth({
           setOidcLoading(false);
         });
     }
-  }, []);
+  }, [
+    onAuthSuccess,
+    setDbError,
+    setIsAdmin,
+    setLoggedIn,
+    setUserId,
+    setUsername,
+    t,
+    isInElectronWebView,
+  ]);
 
   const Spinner = (
     <svg