Troubleshooting & FAQs

1. Why is my download operating over 1 single stream instead of 64 parallel segments?

When a download initializes, NeXDM issues an initial HTTP HEAD or partial GET request to inspect remote response headers. Two specific conditions determine segment partitioning:

• Absence of Byte Range Support: If the origin server returns Accept-Ranges: none or fails to acknowledge the Range header with an HTTP 206 Partial Content status code (returning HTTP 200 OK with the full body instead), the server does not support arbitrary byte extraction.
• Dynamic Streaming or Chunked Transfer Encoding: If the server streams content dynamically using Transfer-Encoding: chunked without specifying an absolute Content-Length, the total file boundary cannot be mathematically partitioned.

In these scenarios, NeXDM safely falls back to a robust single-socket transfer. Attempting to force multi-threading on an unsupported endpoint would result in multiple copies of the full file overwriting the same buffer, causing fatal file corruption.

2. How to resolve HTTP 403 Forbidden / Expired URL errors on long downloads?

Modern Content Delivery Networks (including Amazon CloudFront, AWS S3 pre-signed URLs, Cloudflare R2, and Google Cloud Storage) frequently attach short-lived cryptographic authorization tokens to download URLs (e.g., ?Expires=1700000000&Signature=XYZ...). If an active download is paused, or if a multi-gigabyte transfer exceeds the token's 15-minute or 1-hour expiration window, subsequent chunk requests trigger an HTTP 403 Forbidden or HTTP 410 Gone error.

The Zero-Loss Recovery Procedure:

1. Do not delete the partially completed download in NeXDM.
2. Navigate back to the original source web page in your browser and click the download button to generate a fresh, authenticated session URL.
3. In NeXDM, right-click the stalled download and select "Refresh Download Address".
4. Paste the newly generated URL with the fresh signature parameters. NeXDM will update the connection session and seamlessly resume from your exact completed byte offset without redownloading a single megabyte.

3. Why does the Browser Companion Extension report "Disconnected from Native Host"?

The companion extension communicates with the NeXDM desktop process via Chromium's Native Messaging IPC standard. If the extension loses connection to the desktop daemon, verify the following:

• Desktop Application Status: Ensure the NeXDM desktop app is running in the Windows taskbar or system tray. The Native Messaging host cannot establish standard input/output (stdio) IPC if the desktop executable has been terminated.
• Windows Registry Mapping: If you recently upgraded your browser or performed a Windows operating system feature update, verify that the registry pointer remains intact under:
  HKCU\Software\Google\Chrome\NativeMessagingHosts\com.nexdm.native_host
• Automated Registry Repair: In the NeXDM desktop app, navigate to Settings (⚙️) → Integration and click "Repair Native Messaging Bridge". This regenerates the JSON manifest and restores the Windows Registry entry instantly.

4. Understanding Microsoft Defender SmartScreen "Unrecognized App" Prompts

When installing newly published software releases, Windows Defender SmartScreen may display an "Unrecognized App" prompt. This is a normal consequence of Microsoft's cloud telemetry algorithms:

SmartScreen is a reputation-based filter that scores executables by global download volume. Brand-new releases have not yet been executed by millions of Windows endpoints, meaning Microsoft's telemetry database initially flags their SHA-256 hash as "unrecognized".

• Zero Malware Assurance: Every release of NeXDM is scanned across 70+ commercial antivirus engines on VirusTotal, maintaining an impeccable 0 / 70 Clean Score.
• Official Microsoft Store Alternative: If you prefer to bypass reputation prompts completely, install NeXDM directly via the Microsoft Store (ID: 9NTMZ6V1GZ3V) or via winget install NeXDM.NeXDM.

5. Handling Disk I/O & "Permission Denied (EACCES)" Storage Errors

If NeXDM reports an I/O error or fails to write incoming segments:

• NTFS Volume Permissions: Ensure your target download directory is not configured in protected system directories (such as C:\Program Files or C:\Windows). Set your destination to a user-writable path such as C:\Users\<Username>\Downloads\NeXDM.
• Antivirus File Locking: Certain real-time antivirus scanners lock newly created files while scanning their headers. In NeXDM settings, ensure "Pre-allocate Storage" is enabled so that continuous file clusters are reserved before network chunks arrive.

6. Troubleshooting Dual-Network Speed Bonding

If aggregate throughput does not increase when bonding Wi-Fi and 5G cellular adapters:

1. Verify that both adapters have active internet connectivity and valid default gateways in Windows Network Connections (ncpa.cpl).
2. Ensure both networks are on distinct IP subnets (e.g., Wi-Fi on 192.168.1.x and 5G Tether on 192.168.43.x). If both adapters share the same subnet range, routing table conflicts will prevent concurrent socket binding.
3. Check that your upstream file host supports high concurrency (at least 32 segments) so that both network interfaces receive adequate byte-range allocations.