How to Resume Large File Uploads (Without Starting Over)

You're uploading a 50GB file. Three hours in, your Wi-Fi drops. When you reconnect, you have to start over from scratch.

Sound familiar? Interrupted uploads are one of the most frustrating parts of sending large files—but they don't have to be.

This guide explains resumable uploads, how they work, and how to use them effectively in TeraSender.

Why Uploads Fail

Large file uploads are vulnerable to many disruptions:

Common Causes

1. Wi-Fi Dropouts: Wireless connections are inherently unstable for multi-hour uploads
2. Laptop Sleep: Your computer goes to sleep after 30 minutes of inactivity
3. Browser Crashes: Memory leaks, tab closures, or browser updates
4. Network Congestion: Your ISP throttles or resets connections
5. Power Loss: Laptop battery dies or power outage

Without resumable upload support, any interruption means starting completely over.

What 'Resume Upload' Means in Practice

Resume upload (also called "chunked upload" or "multipart upload") works by:

1. Splitting your file into smaller chunks (e.g., 10MB each)
2. Uploading chunks sequentially and tracking progress
3. If the connection drops, only the current chunk is lost
4. When you reconnect, the upload picks up from the last successfully transmitted chunk

How to Resume in TeraSender

TeraSender uses HTML5 resumable uploads to make recovery seamless.

Step-by-Step

1. Start Your Upload: Drag and drop your large file (e.g., 100GB)
2. Monitor Progress: Watch the progress bar—uploads are broken into chunks automatically
3. If Connection Drops: Close the browser or wait for it to reconnect
4. Re-Select the Same File: Go back to TeraSender, re-select the exact same file from your computer
5. Upload Continues: TeraSender detects the partial upload and resumes from where it left off

Key Requirements

• You must select the same file (same name, same size, same content)
• The file must not have been modified between attempts
• Resumes work within a reasonable time window (typically 24-48 hours)

Troubleshooting

File Name/Size Mismatches

Problem: You re-select the file, but the upload starts over from 0%.

Causes:

• File was edited after the first upload attempt
• File name changed
• File moved to a different location (and cloud sync modified metadata)

Solution: Make sure the file is identical.

Tips for Reliable Large Uploads

1. Use a Wired Connection

Ethernet is far more stable than Wi-Fi. If you're uploading 100GB+, plug in a cable.

2. Keep Laptop Awake

Use a utility like Caffeine (macOS) or Insomnia (Windows) to prevent sleep during uploads.

3. Upload During Off-Peak Hours

For massive files, upload overnight or early morning when network traffic is low.

Start a transfer and test resume with a large file.