Does having one backlog in my first year affect my eligibility for admission in UK for a Master's?

No, having a single cleared backlog from your first year generally does not affect your eligibility for UK master's programs. UK universities typically focus on your overall academic record and degree completion rather than a single early backlog.

To strengthen your application:
- Provide documentation showing the backlog has been cleared.
- Highlight improved academic performance in later semesters.
- Briefly address the backlog in your Statement of Purpose to show growth.

A well-rounded application that explains your progress can help you stand out.