Refs #7849. Complain about a file which does not exist

extension/Classes/Core/AbstractBuildForm.php

@@ -3136,7 +3136,7 @@ abstract class AbstractBuildForm {
         }
         $deleteButton = Support::wrapTag("<button type='button' class='btn btn-default delete-file $disabled' $disabled data-sip='$sipUpload' name='delete-$htmlFormElementName'>", $this->symbol[SYMBOL_DELETE] . $trashText);
 
-        if (Support::isEnabled($formElement, FE_FILE_DOWNLOAD_BUTTON)) {
+        if (!empty($value) && Support::isEnabled($formElement, FE_FILE_DOWNLOAD_BUTTON)) {
             if (is_readable($value)) {
                 $link = new Link($this->sip, $this->dbIndexData);
                 $value = $link->renderLink('s|M:file|d|F:' . $value . '|' . $this->evaluate->parse($formElement[FE_FILE_DOWNLOAD_BUTTON]));