Copying an entire data drive from one disk to another in Windows Server 2019 appears straightforward until Windows Explorer reaches 99% completion and suddenly displays errors such as "Destination Path Too Long", "Item Not Found", or "Access Denied." These issues become increasingly common when migrating servers, replacing storage devices, upgrading hard disks, or performing full data backups containing hundreds of thousands of files.
Windows Explorer is designed primarily for everyday file operations rather than enterprise-scale data migrations. It struggles with deep folder structures, very long filenames, NTFS permissions, junction points, symbolic links, cloud synchronization placeholders, and corrupted filesystem entries.
For IT administrators, system engineers, managed service providers (MSPs), and enterprise support professionals, Robocopy (Robust File Copy) is Microsoft's recommended utility for copying large amounts of data safely, efficiently, and with detailed logging.
This guide explains why these errors occur, how to solve them permanently, and how to perform a reliable drive-to-drive migration using Robocopy on Windows Server 2019.
Many administrators encounter copy failures after several hours of copying because Explorer encounters one or more problematic files.
Typical errors include:
Explorer usually stops and waits for user input, making unattended copying impossible.
Windows traditionally limits file paths to 260 characters (MAX_PATH).
Example:
D:\Company\Data\2025\Client Files\Accounting\Salary\
July\Reimbursement\Employee Documents\
Proofs\Active Employees\
Employee Name\Other\Very Long File Name.pdfAlthough the filename itself may be short, the complete folder hierarchy exceeds Windows' path limit.
When this happens, Explorer displays:
Destination Path Too Long
Long paths often occur because of:
Windows Server 2019 supports long paths, but the feature is disabled by default.
Enable it using Command Prompt:
reg add HKLM\SYSTEM\CurrentControlSet\Control\FileSystem /v LongPathsEnabled /t REG_DWORD /d 1 /for PowerShell:
New-ItemProperty `
-Path HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem `
-Name LongPathsEnabled `
-Value 1 `
-PropertyType DWORD `
-ForceReboot the server after enabling this feature.
Open:
gpedit.mscNavigate to:
Computer ConfigurationAdministrative Templates
System
Filesystem
Enable:
Enable Win32 Long PathsRestart Windows.
Sometimes Windows Explorer reports:
Item Not FoundCould not find this item.
Possible reasons include:
Always scan the drive first.
chkdsk D: /scanIf errors are detected:
chkdsk D: /fRobocopy offers numerous enterprise-grade features.
It can:
For a full drive copy:
robocopy D:\ E:\ /E /COPY:DAT /DCOPY:DAT /MT:32 /R:0 /W:0 /XJ /FFT /TEE /V /LOG:E:\CopyDToE.logCopies all folders including empty directories.
Copies:
Preserves directory timestamps and attributes.
Uses 32 threads for much faster copying.
No retries.
Useful when copying millions of files.
No waiting between retries.
Skips Junction Points.
Prevents endless recursive loops.
Compatible with FAT timestamp precision.
Useful across different storage devices.
Displays progress on screen while writing the log.
Verbose logging.
Creates a detailed copy log.
/MIRcreates an exact mirror.
Advantages:
Disadvantages:
Anything existing on the destination but missing on the source is permanently deleted.
Use only when you fully understand its behavior.
To preserve permissions:
robocopy D:\ E:\ /COPYALLThis copies:
PowerShell:
Get-ChildItem D:\ -Recurse |
Where-Object {$_.FullName.Length -gt 240} |
Select FullName,
@{Name="Length";Expression={$_.FullName.Length}}Get-ChildItem D:\ -Recurse |
Where-Object {
$_.Name -match '[<>:"|?*]'
}Instead of copying again:
robocopy D:\ E:\ /L /MIRThe /L switch performs a simulation.
If nothing appears, both drives are identical.
After completion:
findstr /I "ERROR FAILED" E:\CopyDToE.logThis quickly identifies files requiring manual attention.
| Exit Code | Meaning |
|---|---|
| 0 | Nothing copied; source and destination already match |
| 1 | Files copied successfully |
| 2 | Extra files exist at destination |
| 3 | Files copied and extras found |
| 5 | Some files copied with mismatches |
| 6 | Extras and mismatches detected |
| 7 | Files copied with additional differences |
| 8 or higher | Copy errors occurred |
✔ Enable Win32 Long Paths
✔ Run CHKDSK
✔ Use Robocopy instead of Explorer
✔ Avoid copying open files
✔ Review Robocopy logs
✔ Skip junction points
✔ Preserve permissions if required
✔ Verify copied data
✔ Compare source and destination
✔ Reboot after enabling Long Paths
Large-scale file migrations on Windows Server 2019 can be challenging due to long path limitations, NTFS permissions, corrupted filesystem entries, and Windows Explorer's inability to handle enterprise-scale copy operations. Robocopy provides a reliable, fast, and fault-tolerant solution that preserves data integrity while minimizing interruptions. By enabling long path support, scanning disks beforehand, using the appropriate Robocopy switches, and reviewing copy logs after completion, administrators can successfully migrate entire drives with confidence and avoid the frustrating 99% copy failures that commonly occur with Windows Explorer.