Error code 30015‑11 typically occurs during the installation or update of Microsoft Office and is often caused by corrupt setup files, insufficient permissions, or interference from security software. To fix this issue:

1. Uninstall all existing Office installations completely
   Use the official Microsoft Support and Recovery Assistant to clean up any leftover files, registry entries, and settings, then restart your computer.

2. Download a fresh Office installer
   Get the latest Office setup directly from your Office account portal to ensure the files are complete and unaffected by corruption.

3. Run the installer as Administrator
   Right-click the setup file and select “Run as administrator” to grant full system permissions during the installation process.

4. Temporarily disable antivirus and firewall programs
   These tools can block Office components from downloading or registering properly, so disable them before installation and enable them afterward.

5. Clear temporary installation files
   Use Disk Cleanup or manually delete the contents of %temp% to remove any corrupted temporary files that might disrupt setup.

6. Reset the Windows Installer service
   Open Command Prompt with administrator rights and run:

   bash

   CopyEdit

   msiexec /unregister msiexec /regserver

   This refreshes the Installer service and can resolve installation issues caused by outdated or corrupted installer caches.

For a detailed, step-by-step walkthrough complete with screenshots and additional troubleshooting insights specific to error code 30015‑11, refer to the comprehensive guide available at WinChatSupport’s article on fixing Office error code 30015‑11.