diff --git a/server/libs/expressFileupload/processMultipart.js b/server/libs/expressFileupload/processMultipart.js
index 32fb690a7..317194ebf 100644
--- a/server/libs/expressFileupload/processMultipart.js
+++ b/server/libs/expressFileupload/processMultipart.js
@@ -26,6 +26,18 @@ const waitFlushProperty = Symbol('wait flush property symbol');
  */
 module.exports = (options, req, res, next) => {
   req.files = null;
+  const pendingCleanups = [];
+  const runPendingCleanups = () => {
+    while (pendingCleanups.length) {
+      const cleanupFn = pendingCleanups.pop();
+      try {
+        cleanupFn();
+      } catch (err) {
+        debugLog(options, `Temp file cleanup failed: ${err}`);
+      }
+    }
+  };
+  res.once('close', runPendingCleanups);
 
   // Build busboy options and init busboy instance.
   const busboyOptions = buildOptions(options, { headers: req.headers });
@@ -62,6 +74,7 @@ module.exports = (options, req, res, next) => {
     } = options.useTempFiles
         ? tempFileHandler(options, field, filename) // Upload into temporary file.
         : memHandler(options, field, filename);     // Upload into RAM.
+    pendingCleanups.push(cleanup);
 
     const writePromise = options.useTempFiles
       ? getWritePromise().catch(err => {
@@ -161,6 +174,7 @@ module.exports = (options, req, res, next) => {
 
   busboy.on('error', (err) => {
     debugLog(options, `Busboy error`);
+    runPendingCleanups();
     next(err);
   });
 
diff --git a/server/libs/expressFileupload/tempFileHandler.js b/server/libs/expressFileupload/tempFileHandler.js
index bfaca8b4f..473a62179 100644
--- a/server/libs/expressFileupload/tempFileHandler.js
+++ b/server/libs/expressFileupload/tempFileHandler.js
@@ -28,6 +28,18 @@ module.exports = (options, fieldname, filename) => {
       reject(err);
     });
   });
+  // cleanup() can run from an error path and again on response close.
+  let cleanedUp = false;
+
+  // Windows cannot unlink while the write stream still holds the file.
+  const closeWriteStream = () => new Promise((resolve) => {
+    if (writeStream.destroyed || writeStream.closed) {
+      return resolve();
+    }
+    writeStream.once('close', resolve);
+    writeStream.once('error', resolve);
+    writeStream.end();
+  });
 
   return {
     dataHandler: (data) => {
@@ -51,13 +63,21 @@ module.exports = (options, fieldname, filename) => {
       return Buffer.concat([]);
     },
     cleanup: () => {
+      if (cleanedUp) return Promise.resolve();
+      cleanedUp = true;
       completed = true;
       debugLog(options, `Cleaning up temporary file ${tempFilePath}...`);
-      writeStream.end();
-      deleteFile(tempFilePath, err => (err 
-        ? debugLog(options, `Cleaning up temporary file ${tempFilePath} failed: ${err}`)
-        : debugLog(options, `Cleaning up temporary file ${tempFilePath} done.`)
-      ));
+      return closeWriteStream().then(() => new Promise((resolve) => {
+        // ENOENT: handler already mv()'d the file; that is success.
+        deleteFile(tempFilePath, err => {
+          if (err && err.code !== 'ENOENT') {
+            debugLog(options, `Cleaning up temporary file ${tempFilePath} failed: ${err}`);
+          } else {
+            debugLog(options, `Cleaning up temporary file ${tempFilePath} done.`);
+          }
+          resolve();
+        });
+      }));
     },
     getWritePromise: () => writePromise
   };