“파일이열리지않아요” reports an observed symptom. “이파일에문제가있는것같아요” offers a possible cause. Other files opening does not yet establish the reason this one fails.
Pattern
Example
Present state: adjective + -(으)ㄴ것같아요
글씨가작은것같아요.
Present action: verb + -는것같아요
문자가늦게오는것같아요.
있다 / 없다 + -는것같아요
파일에문제가있는것같아요.
What to check next
연락처가맞는지확인해봐야해요.
Compare 작다→작은것같아요, 바쁘다→바쁜것같아요 and 오다→오는것같아요. Here we focus on guesses about current states or actions. Write a space between 것 and 같아요.