unintentionally

/ˌʌnɪnˈtɛnʃənəli/
adverb
  1. In a way that is not planned or meant; accidentally.
    • He unintentionally deleted the important file while cleaning up his computer.
    • She unintentionally offended her friend by forgetting the birthday party.
    • The scientist unintentionally created a new compound during the experiment.