An expression meaning 'cannot avoid doing (something)' or 'have no choice but to do (something),' indicating compulsion or necessity.
締め切りが明日なので、徹夜で仕上げやらざるを得ない。
The deadline is tomorrow, so I have no choice but to finish it by staying up all night.
重要な資料が見つかったので、調査をやらざるを得ない。
Because important materials were found, we have to carry out an investigation.
急な出張で予定が変わり、代わりに出勤やらざるを得なかった。
A sudden business trip changed the schedule, and I had no choice but to go to work instead.