Why Does Copying Files Take So Long on Windows?

  

Written By Ashwani Tiwari

Approved By Anuraag Singh

Modified On December 31st, 2025

Reading Time 9 Min Read

If you have ever tried copying files on your Windows PC and felt frustrated watching the progress bar crawl along or even worse, freeze completely well you are not alone. This is the problem many of you are facing even on modern systems with SSDs and fast processors.

Here slow file transfer speed remains one of the major complaints. From Windows 7 to Windows 10 and Windows 11 if you are moving your files to a USB drive, transferring data between disks, or backing up your important files or folders you will feel unpredictable, slow, and inconsistent while transferring your Windows files.

How Windows Copies Files

Before we start fixing the problem it is important to understand how Windows file copy works.

When you start to copy your file Windows doesn’t directly move data from one place to another. However It performs several steps you can check below:

1. It reads data from the source drive,
2. stores it in system memory (cache) for a short time,
3. writes it to the destination drive,
4. verifies the data integrity,
5. and updates the file metadata and permissions.

Here you may still think why is my file transfer speed so slow even though I have a powerful PC? Here you need to understand that the process happens repeatedly and file by file. The more complex the transfer including (multiple files, slow drives, USB devices) the higher chances of delays.

Why Does Copying Files Take So Long on Windows?

As a data recovery expert I haven’t seen a single cause but there are multiple factors combined to slow things down on Windows.

1. Storage Device Speed Limits

Let me tell you, not all storage devices are equal.

If you are trying to copy files from an SSD to a USB flash drive, the USB device becomes the bottleneck. This is one of the major reasons why file transfers are slow in Windows especially when you are copying to external drives.

2. Why File Transfer Speed Goes Up and Down

If you ever notice that file transfer speed starts fast and then suddenly it slows down or start fluctuation well there are the multiple reasons behind this:

• initially used RAM cache by Windows (fast burst)
• The cache fills up
• The system waits for the destination drive to catch up
• Thermal throttling reduces speed
• Background processes interrupt I/O

Because of these reasons your file transfer speed goes up and down instead of staying consistent.

3. Why Do Small Files Take Longer to Copy?

This is one of the most confusing behaviors that small files often take longer to copy than large files. If you have ever experienced sometimes:

• Copying a single 10 GB video file might be completed quickly.
• Copying 10,000 photos (each 2 MB) might take longer.

Have you ever wondered why this happens?

This must be making you quite curious about why and how this often happens? Well this all happens because each file requires:

• File system checks
• Metadata creation
• Antivirus scanning
• Permission validation

You must have now understood why small files take longer to copy, and what is going on in the background of your system when you copy a file from one drive to another.

Windows Version – Specific File Transfer Issues

Windows 11 File Transfer Speed is Slow

Windows 11: Why does copying files take so long? You will find these features are introduced in desktop operating system windows 11:

• Improved security layers
• Virtualization-based security
• Updated Explorer UI

While these features enhance security, they can slow down disk operations. This is why many of you are asking why copying files takes so long in Windows 11, especially on older hardware.

Windows 10 File Transfer Speed Slow

The common reasons you encounter in Windows 10 are something like this:

• USB power management throttling
• Background Windows Update services
• Explorer bugs affecting large transfers

As a result, users often report slow file transfer speeds in Windows 10, especially when copying files to USB drives.

Slow File Transfer on Windows 7

Compared to other current desktop operating systems, Windows 7 severely lacks modern optimizations, especially for SSDs and USB 3.0 devices.

• Large file handling
• High-speed external drives
• Modern file systems

This highlights and explains ongoing complaints about the slow file transfer in Windows 7.

When File Transfer Speed Drops to 0 Bytes

Few things are more serious than seeing file transfer speed 0 bytes while your copy operation. This usually indicates:

• Bad sectors on the source drive
• File system corruption
• USB connection instability
• Drive firmware issues

At this time, forcing the transfer could lead to further problems. If the transfer repeatedly stalls at 0 bytes, it often indicates a larger storage issue, not just a slow Windows system.

Windows 10 Slow Copying Files to USB

Have you ever wondered why this happens? USB transfers are quite problematic, and the main reasons for this are:

• Many flash drives have low-quality controllers.
• USB power saving settings reduce performance.
• FAT32 or exFAT file systems behave differently.
• Cheap USB cables reduce speed.

This is why slow file copying to USB drives in Windows 10 is one of the most frequently searched issues.

Why Windows Slows Down When Copying Large Files

Windows Explorer focuses more on security over speed so when you copy large and heavy files, it depends completely on system caching and write verification. First the data is stored in RAM and then it is written to the disk in batches.

Windows pauses the transfer to flush the data once cache fills up which slows down the speed and it drops to 0 bytes per second for a short period.

Another major drawback is single-threaded processing. Windows Explorer copies large files one by one instead of utilizing parallel operations. I have noticed that the modern SSDs and USB 3.x devices support multiple simultaneous writes, but the thing is explorer doesn’t fully utilize this capability so the output will be slower transfer speeds.

As Windows has continuous integrity checks during this process of file copying which helps prevent data corruption adding extra overhead especially for those files larger than 10 to 20 Gigabyte.

Combination of this sequential processing caching limitations, and the verification overhead explains why Windows file copying struggles with some large files, even if you have high performing systems.
Performance comparison

Quick Fixes to Improve File Transfer Speed

What should be our immediate course of action that is safe for everyone to improve file transfer speed, and make the transfer stable?
Immediate Actions

• Stop and restart the transfer.
• Close background apps.
• Temporarily disable your antivirus.
• Use different USB ports or cables.

System Level Tweaks

• Enable write caching for the external drive.
• Disable USB selective suspend.
• Use NTFS instead of FAT32 for large files.

These steps equally reduce slow file transfer speeds in many cases.

What Works Better Than Windows’ Built-In File Copy

Windows Explorer is not always the best option. For critical or challenging transfers you can try with some better alternatives that includes:

• Command-line copy tools with improved buffering
• Dedicated transfer utilities with error handling
• Copying in smaller batches instead of one large operation

As these methods often provide more stable performance and fewer interruptions compared to the standard Explorer copy operation.

Practical Situations Where File Transfers Slow Down

Moving your Data from Old HDD to New SSD

The important thing to understand here is slow transfer. It is common because the hard drive limits the read speed. Suppose if the drive has bad sectors or missing files, users often resort to HDD recovery solutions before attempting another transfer.

Copying Backups to External Drives

Differences in USB versions and file system errors can cause a sudden decrease in speed or even stop the copying process.

Transferring Media Libraries

Thousands of small files create metadata overhead which significantly slows down the file copying process.

When Slow File Transfer Signals a Bigger Problem

If your file transfers are always slow, then this points to the deeper issues like:

• Failing hard drive
• Corrupt file system
• Bad sectors
• USB controller degradation

If you find your file transfer is always unreliable it is not a Windows issue alone it’s simply a storage health warning situation.

Final Thoughts

Why does copying files take so long and what should you do in this critical case? If the copy files are very slow or unreliable it is basically a combination of hardware limitation, structure of the files, and most importantly your system behavior. File transfers depend on:

• Speed of the Storage device
• Structure of the File
• Windows version behavior
• Background processes
• Health of Hardware

First Identifying the bottlenecks and after choosing the right yet reliable solutions. By understanding these common reasons, you can minimize errors and make more informed decisions when transferring your important data.