This usually means the original installation source has been moved or deleted. Adding Languages
Microsoft Support and Recovery Assistant (SARA) can automatically fix missing .msi references.
Officemui.msi is a part of Microsoft Office, specifically the Multi-Language User Interface (MUI) pack. Here are a few features that could be useful:
Are you currently seeing this error while a new version or repairing an old one?
If you cannot locate the source file: