اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْفِتَنِ مَا ظَهَرَ مِنْهَا وَمَا بَطَنَ
Transliteration
Allahumma inni a'udhu bika minal-fitani ma zahara minha wa ma batan
English meaning
O Allah, I seek refuge in You from tribulations, both apparent and hidden.
When is it recited?
Recited anytime, especially during times of tribulation.
Source
Muslim, Dhikr 49, 2706