Well I think you'll definately want to clean up the previous file, if you want to cut down the waiting then you could start a new instance of the form (probably convert it to an mdi format) and let the other close in the background. The thing I fear, which goes along the lines of the code I added to the form_closing event is that the gc is not going to properly clean up for you and thus you will develop a memory leak. Which especially if you are opening 3meg files will be a very bad thing.