Sentence examples for this was unfortunate from inspiring English sources

The phrase "this was unfortunate" is correct and can be used in written English.
It can be used to express a sense of disappointment or regret about something that has happened. For example: - "I forgot my keys at home and couldn't get into the office. This was unfortunate, as I had an important meeting scheduled for that morning." - "The game was canceled due to bad weather. This was unfortunate news for the fans who had been eagerly waiting to watch their team play." - "She lost her phone on the way to the airport. This was unfortunate timing, as she needed it to show her electronic boarding pass at security."