Remove the ability to import previous imported file I'm guessing someone must have done this before but I can't find a module for it.  

In Feeds the last file you imported can be seen by name on the left hand side.  Next to the 'Browse' box.  

If the user doesn't browse for a file then the File shown in that box is imported when clicking on the 'submit' button.  What I'd like to do is to leave this file being shown as the last import but I don't want it to be imported if no file has been selected. 

Has anyone done this or something similar .
you can simplely remove it by using hook_form_alter 

don't forget replace  form_id and yourmodulename with yours  in following code

function yourmodulename_form_alter(&amp;$form,$form_state,$form_id){
    if($form_id=='feeds_import_form' ){
    unset($form['feeds']["FeedsFileFetcher"]['upload']['#file_info']);
}
}


update
in this section we prevent user to resubmit the old file,this mean if user push import button without browsed new file we prevent him to remport

function mymodule_form_alter(&amp;$form,$form_state,$form_id){
    if($form_id=='feeds_import_form' ){
      $form['#validate'][] = 'mymodule_prevent_import_validate';    
}
}

function mymodule_prevent_import_validate($form,$form_state){
    if(!isset($form_state['values']['feeds']["FeedsFileFetcher"]['file'])){
            form_set_error('upload', t('Not new file uploaded'));
            return false;
    }
}