diff --git a/src/aphront/httpparametertype/AphrontFileHTTPParameterType.php b/src/aphront/httpparametertype/AphrontFileHTTPParameterType.php
--- a/src/aphront/httpparametertype/AphrontFileHTTPParameterType.php
+++ b/src/aphront/httpparametertype/AphrontFileHTTPParameterType.php
@@ -7,10 +7,17 @@
     return $key.'_raw';
   }
 
+  private function getDefaultKey($key) {
+    return $key.'_default';
+  }
+
   protected function getParameterExists(AphrontRequest $request, $key) {
     $file_key = $this->getFileKey($key);
+    $default_key = $this->getDefaultKey($key);
+
     return $request->getExists($key) ||
-           $request->getFileExists($file_key);
+           $request->getFileExists($file_key) ||
+           $request->getExists($default_key);
   }
 
   protected function getParameterValue(AphrontRequest $request, $key) {
@@ -27,8 +34,9 @@
     // this code around as a fallback if the client-side JS goes awry.
 
     $file_key = $this->getFileKey($key);
+    $default_key = $this->getDefaultKey($key);
     if (!$request->getFileExists($file_key)) {
-      return null;
+      return $request->getStr($default_key);
     }
 
     $viewer = $this->getViewer();
diff --git a/src/view/form/control/PHUIFormFileControl.php b/src/view/form/control/PHUIFormFileControl.php
--- a/src/view/form/control/PHUIFormFileControl.php
+++ b/src/view/form/control/PHUIFormFileControl.php
@@ -30,15 +30,47 @@
         'chunkThreshold' => PhabricatorFileStorageEngine::getChunkThreshold(),
       ));
 
-    return phutil_tag(
-      'input',
-      array(
-        'type' => 'file',
-        'multiple' => $this->getAllowMultiple() ? 'multiple' : null,
-        'name' => $this->getName().'.raw',
-        'id' => $file_id,
-        'disabled' => $this->getDisabled() ? 'disabled' : null,
-      ));
+
+    // If the control has a value, add a hidden input which submits it as a
+    // default. This allows the file control to mean "don't change anything",
+    // instead of "remove the file", if the user submits the form without
+    // touching it.
+
+    // This also allows the input to "hold" the value of an uploaded file if
+    // there is another error in the form: when you submit the form but are
+    // stopped because of an unrelated error, submitting it again will keep
+    // the value around (if you don't upload a new file) instead of requiring
+    // you to pick the file again.
+
+    // TODO: This works alright, but is a bit of a hack, and the UI should
+    // provide the user better feedback about whether the state of the control
+    // is "keep the value the same" or "remove the value", and about whether
+    // or not the control is "holding" a value from a previous submission.
+
+    $default_input = null;
+    $default_value = $this->getValue();
+    if ($default_value !== null) {
+      $default_input = phutil_tag(
+        'input',
+        array(
+          'type' => 'hidden',
+          'name' => $this->getName().'_default',
+          'value' => $default_value,
+        ));
+    }
+
+    return array(
+      phutil_tag(
+        'input',
+        array(
+          'type' => 'file',
+          'multiple' => $this->getAllowMultiple() ? 'multiple' : null,
+          'name' => $this->getName().'_raw',
+          'id' => $file_id,
+          'disabled' => $this->getDisabled() ? 'disabled' : null,
+        )),
+      $default_input,
+    );
   }
 
 }