Subject: Apology Letter for Sending Wrong Email 发错电邮
Dear Mrs. White,
This is to kindly express my sincere apology for sending an email that was not meant for you.
I am so sorry that this had to happen. I was in the process of responding to emails when my computer broke down （出现故障） and failed to function well （无法正常运行）.
The mails were then sent to wrong recipient （错误的收件人） in the process of fixing the computer and there was no way I could stop this. I am sorry for the inconvenience that this email may have caused you. I hope you forgive me.
Thank you for your consideration.