Credit: Lucas Gouveia / How-To Geek

Published 2 minutes ago

Arol is a tech journalist who currently works as a contributor at How-To Geek since 2022. He first began writing online for the short-lived portal of Spanish-language gaming forum Emudesc in 2013. Years later, in 2017, he got his true start in tech journalism working for a small Google-focused site called Pixel Spot. He transitioned to a news and feature writer role at XDA Developers that same year, where he worked until 2021 before making the jump to other websites.

Arol brings nearly a decade of writing experience, and the occasional hot take, to his writings. While he’s a technology lover at heart, he holds computer hardware and smartphones particularly close to heart. You’ll normally find him covering news, although he has also written the occasional deal, buyer’s guide, how-to post, and round-up. He’s also written for Android Police and MakeUseOf. He’s also a Political Science student. When he’s not writing, you’ll probably find him hitting the gym, trying to ace a new hobby, reading his textbooks, or traveling. You can reach him at me@arolwright.com.

Copying around a couple of small files, like screenshots or documents, is, for the most part, normally fine. They’re normally small files, and you won’t have much trouble moving them around. The problem, however, comes when you actually have to move around a file that’s several gigabytes in size, or worse, several of them—using the regular tools meant for that purpose, your PC will be struggling.

Thankfully, there are solutions—if you’re willing to learn your way around them.Why is Windows Copy unreliable?

Credit: Lucas Gouveia / How-To Geek

The copy-paste function found in File Explorer is often, well, not great when you ask it to meet the rigorous demands of moving large datasets or massive individual files. As I said before, while it serves you well for moving a handful of documents or images, its architecture and the way it processes files mean it will have a hard time when transferring terabytes of data or thousands of nested folders.

This is because of the way Windows Explorer manages the file enumeration process. Before a transfer begins, the system attempts to calculate the total size and number of files to provide a progress estimate. For massive directories, said pre-calculation phase can make the entire process grind to a halt, leading to the infamous "Calculating time remaining" dialog box that lingers indefinitely. This estimation algorithm is notoriously inaccurate, fluctuating wildly between minutes and days based on momentary throughput rather than a sustained average, and giving you really no reliable data on when the task will actually complete.

Furthermore, Windows Explorer lacks robust error handling during the transfer process. If a single file within a batch of thousands is locked by another process or encounters a read error, the entire operation frequently pauses, waiting for user intervention. And in worst-case scenarios, the transfer may abort completely, leaving you with a partially copied directory and no easy way to determine which files were successfully transferred and which were not.

Related

Resume capabilities have improved in recent iterations of Windows, but it’s still awful; resuming a large interrupted transfer often requires re-verifying the destination files, a process that Explorer handles inefficiently. Additionally, the standard copy function does not perform a checksum verification after writing the data. It assumes that if the write operation completed without a system-level error, the data is intact. For video editors, archivists, or data hoarders moving critical backups, this lack of verification is a gamble that can result in silent data corruption, where the file exists at the destination but contains bit-level errors that render it unusable. It’s not something that happens often, but it happens. In fact, you’ve probably had it happen without realizing it.

The alternative: command-line tools

So how do you fix this? The answer is simple: Windows’ command line. If you’re not a power user, it might be scary, but once you get the hang of it, it might just become the only way you’ll move around thousands of files at once on your computer. Windows actually even has a native utility for this, known as Robocopy, or "Robust File Copy." Unlike the standard drag-and-drop interface, Robocopy is a command-line program designed specifically for mirroring directories and handling large batch transfers with server-grade stability. It operates without the overhead of the graphical user interface, allowing it to allocate more system resources directly to the input/output operations.

This tool allows users to execute complex transfer logic that Windows Explorer simply cannot handle. For instance, you can specify exactly how many retries the system should attempt if a file is locked, or set a wait time between retries, ensuring that a temporary glitch does not derail an overnight transfer of several terabytes.

Related

4 Worthy Alternatives to Windows File Explorer

Improve your file management with one of these programs.

The true power of command-line tools like Robocopy lies in their specialized switches and parameters, which offer granular control over the data movement. You can employ multithreading capabilities to copy multiple files simultaneously, saturating the available network bandwidth or disk throughput much more effectively than the single-threaded nature of a standard Explorer copy. This significantly reduces the total time required for transfers involving thousands of small files.

Furthermore, these tools offer a "restartable" mode. If a connection is severed during the transfer of a massive video file, Robocopy can pick up exactly where it left off once the connection is restored, rather than restarting the file from the beginning. It also excels at synchronization, allowing a user to mirror a source directory to a destination, automatically purging files in the destination that no longer exist in the source. This creates an exact 1:1 replica of the data structure, a feat that is tedious and prone to human error when attempted manually via File Explorer.

Should I use them?

If the issues I described in the first section of the article ring a bell, you might want to use it every so often. Still, it’s not for everyone. For the average Joe moving a folder of holiday photos to a USB drive, the learning curve associated with command-line syntax is likely unnecessary. Even with all its downfalls, the visual feedback of a progress bar and the familiarity of mouse interaction provide a user experience that is adequate for low-stakes, small-volume transfers. And you might even still get away with it if you have to transfer videos weighing a few gigs each. The risk of typing a command incorrectly and accidentally overwriting or deleting data is also a genuine concern for those unaccustomed to the unforgiving nature of the terminal. A misplaced flag in a mirroring command can wipe a destination drive in seconds, with no Recycle Bin to recover the lost data.

For professionals, content creators, and anyone who regularly manages hundreds of gigabytes of data, the switch is not just recommended but often necessary. The initial friction of learning syntax is quickly outweighed by the peace of mind provided by verifiable logs and error resilience, and of course, transfers that actually take the time they’re supposed to take, without indexing shenanigans delaying you. If you frequently find yourself staring at a frozen copy dialog or manually checking folder sizes to ensure a backup completed successfully, the command line is a pretty good alternative. You can script these commands and have complex backup routines automated and scheduled to run while you sleep, with a detailed log file waiting for you in the morning to confirm that every byte was transferred correctly.