ZIP Download Failures When Access to Files Is Denied

Product version: 11.1

Last modified: 23 December 2025

Problem

During File-Level Recovery, downloading recovered items as a ZIP archive may result in:

  • Corrupted ZIP files

  • ZIP files containing only partially recovered content

  • Browsers show the download as successful even when FLR failed

This occurs when the source VM contains files or folders with denied access permissions, including:

  • Entire folders with denied rights

  • Folders containing a mix of accessible and inaccessible files

Background

The following explains the underlying behavior that causes ZIP files to become corrupted when access-denied items are included in an FLR download.

FLR job builds ZIP files on the fly while streaming content from the Transporter. When an access-denied item is encountered, the FLR process stops sending valid data. However, the browser still completes the download and finalizes the partially written file as a ZIP. As a result, users receive a file that may be corrupted, or missing specific files.

Solution

Follow the steps below to ensure successful FLR downloads:

  1. Before FLR, verify whether selected folders/files have the correct permissions.

  2. Avoid selecting items with restricted permissions.

  3. Ensure the user account used by the Transporter has 'Read' permissions for the requested files in the source VM.

  4. If the source VM uses Data Deduplication or Distributed File System (DFS), ensure that the corresponding features are installed on the operating system hosting the Transporter.

  5. Always verify the ZIP file after download.