If Windows won’t copy files, the most common causes are permissions, locked files, disk errors, or file-system limits — and most can be fixed without reinstalling Windows. This article explains why File copy doesn’t work in Windows 10 and shows practical fixes you can follow step by step.
You’ll learn the ten most frequent reasons copy operations fail (local and network), the fastest ways to restore copying, and some commands and tools to diagnose and resolve deeper problems.
Key Takeaway
The fastest way to restore file copying is to identify whether the issue is local (permissions, disk errors, full disk, file in use) or network-related (share permissions, credentials, SMB issues). Use built-in tools — Task Manager, Resource Monitor, chkdsk, sfc /scannow, icacls, and Robocopy — to diagnose and fix most problems safely.
Quick Fix Guide
| Reason for the Problem | Quick Solution |
|---|---|
| Permission or ownership errors | Take ownership and grant permissions with takeown and icacls. |
| File is locked or in use | Close the app using it or kill the process in Task Manager / Resource Monitor. |
| Corrupted system files | Run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth. |
| Disk errors or bad sectors | Run chkdsk C: /f /r and schedule a reboot if needed. |
| Insufficient disk space | Free space or move files; empty Recycle Bin and use Disk Cleanup. |
| File size or file system limits (FAT32) | Convert to NTFS or split the file, use exFAT/NTFS for large files. |
| Long file path or illegal characters | Use shorter paths, enable long paths in registry, or use \?\ prefix. |
| Antivirus or security software blocking | Temporarily disable or adjust settings (Controlled Folder Access). |
| Network share/authentication problems | Reconnect the share, clear cached credentials, check net use. |
| File Explorer or Windows update bug | Restart explorer.exe, try Safe Mode or use Robocopy from CMD. |
Detailed Fixes for “File copy doesn’t work in Windows 10”
1. Permission or ownership errors
Why it causes the problem
- If your account does not have read/write permissions on the file or destination folder, Windows will block copy operations and show “Access denied”.
Step-by-step solution
- Right-click the folder, choose Properties → Security → Advanced to view owner and permissions.
- To take ownership from an elevated Command Prompt, run:
- takeown /f “C:\path\to\folder” /r /d y
- Grant full control using icacls:
- icacls “C:\path\to\folder” /grant “%username%”:F /t
- If GUI preferred: open Properties → Security → Edit, select your user and check Full control, then Apply.
Notes/tips
- Running File Explorer as Administrator does not change NTFS permissions; you need to take ownership or adjust ACLs.
- Use these commands carefully on system folders.
2. File is locked or in use by another process
Why it causes the problem
- Windows cannot move or overwrite a file that an application has open. Background services, editors, or even Explorer previews can lock files.
Step-by-step solution
- Try closing applications that may use the file (Office apps, media players, IDEs).
- Use Task Manager: press Ctrl+Shift+Esc, find the process, select End task.
- For more precise locks, open Resource Monitor: Start → type “Resource Monitor” → CPU tab → Associated Handles, search the filename, identify and kill the process.
- If lock persists, reboot into Safe Mode and move the file:
- Settings → Update & Security → Recovery → Restart now (Advanced startup) → Troubleshoot → Advanced options → Startup Settings → Restart → choose Safe Mode.
Notes/tips
- Tools like Process Explorer (Sysinternals) can show the exact handle and release it.
3. Corrupted or missing system files
Why it causes the problem
- Core shell components (Explorer) or system libraries may be damaged, causing copy commands to fail or Explorer to crash.
Step-by-step solution
- Open Command Prompt as Administrator.
- Run System File Checker:
- sfc /scannow
- If SFC reports issues it can’t fix, run DISM:
- DISM /Online /Cleanup-Image /ScanHealth
- DISM /Online /Cleanup-Image /RestoreHealth
- Reboot and test copying again.
Notes/tips
- DISM may need internet access to download replacement files; ensure connectivity.
4. Disk errors, bad sectors, or filesystem corruption
Why it causes the problem
- Physical disk issues or corrupt metadata can block read/write operations and make Windows abort copies.
Step-by-step solution
- Open Command Prompt as Administrator.
- Schedule and run CHKDSK:
- chkdsk C: /f /r
- If prompted to schedule on next restart, type Y and reboot.
- Review the CHKDSK log in Event Viewer → Windows Logs → Application (source: Wininit).
Notes/tips
- Back up important data before running /r if disk is failing; consider cloning the drive for recovery.
5. Insufficient disk space
Why it causes the problem
- Windows will stop copying when there isn’t enough free space on the destination or during intermediate buffering for large files.
Step-by-step solution
- Check free space in File Explorer or Settings → System → Storage.
- Empty Recycle Bin, remove temporary files: Start → type “Disk Cleanup” → select drive → Clean up system files.
- Move large files to an external drive or cloud storage, or delete unneeded programs via Settings → Apps.
Notes/tips
- For large transfers, ensure both source and destination drives have space. Robocopy can copy directly between drives without extra temporary space.
6. File system limits (FAT32 max file size or permission differences)
Why it causes the problem
- FAT32 volumes cannot store files larger than 4 GB; copying a large file to a FAT32 drive will fail. NTFS supports large files and preserves permissions.
Step-by-step solution
- Check the drive format: right-click drive → Properties → see File system.
- Convert without data loss (NTFS):
- convert E: /fs:ntfs (replace E: with target drive letter)
- Alternatively, reformat to exFAT or NTFS (this deletes data): Right-click drive → Format.
Notes/tips
- Always back up before reformatting. Use convert only when not switching to exFAT.
7. Long file path or illegal characters
Why it causes the problem
- Windows traditionally enforces a MAX_PATH limit (~260 characters). Very long paths or reserved characters can cause copy failures.
Step-by-step solution
- Try moving the file to a shorter path (e.g., C:\Temp) and retry.
- Enable long paths (Windows 10, Anniversary Update and later):
- Open Registry Editor (regedit) and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem.
- Set LongPathsEnabled to 1 (DWORD).
- Or use Group Policy: Computer Configuration → Administrative Templates → System → Filesystem → Enable Win32 long paths = Enabled.
- Use the UNC long-path prefix in PowerShell or CMD:
- robocopy “\?\C:\very\long\path” “\?\D:\dest\path” /E
Notes/tips
- Be careful editing the registry. The long path feature depends on app support; not all programs honor it.
8. Antivirus or security software blocking
Why it causes the problem
- Real-time scanners or ransomware protection (Controlled Folder Access) can intercept or block file writes.
Step-by-step solution
- Temporarily disable third-party antivirus or Windows Defender:
- Windows Security → Virus & threat protection → Manage settings → Real-time protection (toggle off).
- If Controlled Folder Access blocks copying, adjust: Windows Security → Virus & threat protection → Ransomware protection → Manage ransomware protection → Controlled folder access and add exclusions.
- Test copy; re-enable protection afterward and add safe paths to exclusions.
Notes/tips
- Don’t leave protection disabled. Only disable briefly for testing and re-enable after excluding trusted folders.
Why it causes the problem
- Copying over the network can fail because of invalid credentials, SMB protocol mismatches, quota limits, or intermittent connectivity.
Step-by-step solution
- Reconnect the share: File Explorer → Map network drive → Disconnect then Map again.
- Clear cached credentials: Control Panel → Credential Manager → Windows Credentials → remove entries, then reconnect and provide credentials.
- From an elevated CMD, view connections: net use and remove with *net use /delete**.
- Ensure SMB is enabled and compatible on both systems: Control Panel → Programs → Turn Windows features on or off → SMB 1.0/CIFS (only enable SMB1 if required).
- Use Robocopy for network copies with retries and resume:
- robocopy “\server\share\folder” “D:\dest” /MIR /Z /R:3 /W:5
Notes/tips
- Use /Z for restartable mode in Robocopy; /MIR mirrors but be careful — it can delete at destination.
10. File Explorer, copy dialog, or Windows update bug
Why it causes the problem
- Explorer crashes, a stuck copy dialog, or a recent update can cause copy operations to fail unpredictably.
Step-by-step solution
- Restart Explorer: open Task Manager → Processes → Windows Explorer → Restart.
- If Explorer repeatedly crashes, boot into Safe Mode and test copying.
- Use command-line tools to bypass Explorer: robocopy or xcopy:
- robocopy “C:\source” “D:\dest” /E
- Uninstall recent problematic updates: Settings → Update & Security → View update history → Uninstall updates.
- Create a new user account to test whether corruption is profile-specific: Settings → Accounts → Family & other users → Add someone else to this PC.
Notes/tips
- Robocopy is more robust than Explorer and provides logging to troubleshoot problems.
Maintenance & Prevention (section added)
- Keep Windows updated but review major updates if problems began after an update — use rollback if necessary.
- Regularly run chkdsk and a SMART check with tools like CrystalDiskInfo to catch disk failures early.
- Maintain sufficient free space and a clean antivirus configuration with exclusions for trusted backup locations.
- Use robust copy tools (Robocopy, FastCopy) for large or many-file transfers; they handle retries and resume.
- Back up critical data before performing disk repairs or permission changes.
FAQ
Q: Can I resume an interrupted copy?
A: Yes — use Robocopy with the /Z (restartable mode) and /R: (retries) options to resume interrupted network or local copies reliably.
Q: Why does copying large files to USB sometimes fail halfway?
A: Common causes are FAT32 format (4 GB limit), failing USB drive, or USB power/port issues. Reformat to exFAT or NTFS for large files and test the drive’s health.
Q: How do I copy files while preserving permissions and timestamps?
A: Use Robocopy with /COPYALL or /COPY:DATSOU to preserve data, attributes, timestamps, security, owner, and auditing info.
Q: Is there a safe way to force Windows to overwrite read-only files?
A: You must change attributes first: attrib -r “C:\path\file.ext” or use icacls to grant write access, then copy.
Q: When should I consider hardware replacement?
A: If SMART reports failing sectors, CHKDSK finds many bad sectors, or copying fails even after software fixes, clone the drive immediately and replace it.
Conclusion
Most copy failures in Windows are caused by permissions, file locks, disk or file-system limits, antivirus interference, or network/authentication issues — and they can usually be fixed with tools like takeown, icacls, chkdsk, sfc /scannow, and robocopy. If you follow the steps above, you’ll resolve the majority of cases where File copy doesn’t work in Windows 10 and prevent future problems.
