Office 365 may show error 30174‑45 during installation or updates when its setup encounters problems with the license or installer files—often due to corrupted installation packages, permission issues, or conflicts with previous Office versions. This error stops the install/update process and prevents Office from working properly. To fix it, start by restarting your PC and running the Office installer or updater as an administrator to bypass permission restrictions. If the error persists, uninstall all Office installations using the Microsoft Support and Recovery Assistant or via Programs and Features, then delete leftover folders in
%ProgramFiles%Microsoft Office, %ProgramFiles(x86)%Microsoft Office, and %AppData%LocalMicrosoftOffice. Next, temporarily disable any antivirus or firewall that may interfere during the setup. Open an elevated Command Prompt and run sfc /scannow to repair any corrupted system files that could block installation. After rebooting, run the installer or updater again. These steps typically resolve error 30174‑45 and allow Office to install or update successfully. For a detailed, step‑by‑step walkthrough, see this guide.