Microsoft Office Error Code 30015‑28 (2231435265) usually occurs during the installation or repair process of Office 365, 2016, or 2019. This error is typically triggered by corrupted installation files, leftover components from previous Office versions, or interference from antivirus or firewall programs.

To resolve the issue, start by uninstalling all existing Office versions from the Control Panel or Settings. Once uninstalled, manually delete any remaining Microsoft Office folders in C:Program Files and C:Program Files (x86), and clear temporary files by deleting the contents of the %temp% directory.

Next, temporarily disable your antivirus and firewall software. Then open Command Prompt as administrator and run sfc /scannow to repair any corrupted system files. If needed, follow it with the DISM tool to clean and restore the system image.

After preparing your system, download a fresh Office installer from your copyright and begin a clean installation using administrator rights.

For a full step-by-step guide and additional troubleshooting methods, refer to the article on WinChatSupport.