To dream about a file cabinet indicates that you should keep your reality and details correct. The file cabinet could indicate the thoughts or extraneous details that you require occasional access to.
To dream that the drawers of the file cabinet are open wide suggests your willingness to accept other thoughts, concerns, ideas, and concerns.
To dream that the file cabinet is locked indicates that you would like to keep something hidden from others. This dream could also suggest that you are being stubborn.