No problem :) I'm not really sure what you are asking with the second part, so I'll try to answer three things you could mean :) 1. You get a problem when you have too many files seleced in the file dialog 2. You get a problem when the file name for one of them files selected is long 3. You get a problem when adding a large number of files, or a file with a long name, to the list box. 1. As for as I know there is no limited on the number of files you can select, I've never seen it anyway. The only problem you might get is because windows adds each file you select to the edit control, so if you select a lot you may overrun the edit control - is that what you mean? If so, see 2. 2. Hmmm... Well, the max length of a file name is MAX_PATH (255 chars) in Windows anyway, the edit control that accepts the file list should be able to take that easily, but with a lot of files it concevable you will overrun it. The only thing I can suggest is to use the "explorer style" file dialog (the one with the places bar down the side) this may be able to handle a large list of files better. Though you are now faced with another problem. Using the explorer dialog via MFC is tricky. You have to set define _WIN32_WINNT >= 0x0500 (which also means this will only work on 2k+) but thats not all there is to it because the setting this define adds some extra members to the OPENFILENAME struct which cause windows to display the explore style dialog rather than the new one. Unfotunatly, the size of OPENFILENAME is set with in MFC and short of recompiling MFC dlls, you are stuck with it. There are ways round it, search for OPENFILENAME on MSDN and look for 2000 Peridocal (called C++ Q AND A) buy Paul DiLascia. It's called "Windows 2000 File Dialog Revisited; Autocompletion and the ACTest Demo App" and it will show you how to use the new open dialog which might fix your problem. Of course if it doesn't, then.. err.. :) The other thing it might be is this: FIX: Common File Dialog Multiple Selection File Limit : Q179372 But this has aparently been fixed in a service pack. WHat version you running? 3. If this is your problem you are hitting a limit with the number of entrys a list box can handle, use a CListCtrl instead.