When attempting to copy a single file with robocopy, many users encounter this unexpected behavior where the command interprets the source as a directory rather than a file. The root cause lies in robocopy's fundamental design as a directory replication tool rather than a file copy utility.

# This fails because robocopy expects directories
robocopy "c:\\source.txt" "d:\\destination.txt"
# ERROR: Accessing Source Directory c:\\source.txt\\

To copy a single file, you need to specify both the source directory and the destination directory, then use the file filter parameter:

# Correct syntax for single file copy
robocopy "c:\\" "d:\\backup" "important.txt"

Key components of this command:

• Source directory: "c:\\" (root of C drive)
• Destination directory: "d:\\backup"
• File name filter: "important.txt"

For more complex file operations, consider these additional parameters:

# Copy with retries and logging
robocopy "c:\\work" "d:\\archive" "report.pdf" /R:3 /W:5 /LOG:"copy_log.txt"

# Mirror a single file (delete if exists in destination)
robocopy "c:\\temp" "e:\\backup" "config.ini" /MIR

While you could use simpler commands like COPY or XCOPY for single files, robocopy offers significant advantages:

• Resilient copying with retry options (/R and /W parameters)
• Detailed logging capabilities (/LOG parameter)
• Restartable transfers (/Z parameter)
• Multi-threaded operations (/MT parameter)

Here's a complete example for backing up a critical database file daily:

@echo off
SET source=C:\databases
SET dest=D:\daily_backup
SET file=app_data.db

robocopy %source% %dest% %file% /R:5 /W:10 /LOG:%dest%\copy_log.txt /NP /TEE
if %ERRORLEVEL% LEQ 7 (
    echo Backup completed successfully
) else (
    echo Backup encountered errors
)

If you're still experiencing problems:

• Ensure the source file exists before running robocopy
• Verify you have proper permissions on both source and destination
• Check for special characters in filenames that might need escaping
• Consider using the /L parameter to test first (dry run)

Many Windows administrators and developers encounter this issue when trying to use robocopy for single file transfers. The command-line tool automatically treats paths as directories, which becomes problematic when you specifically want to copy just one file.

Robocopy (Robust File Copy) was primarily designed for directory synchronization tasks. Its core functionality revolves around folder operations, which explains why it automatically appends backslashes to paths. This behavior persists even when you're clearly specifying a file.

The proper way to copy a single file with robocopy involves using the exclude files parameter in combination with the file name:

robocopy "c:\source_folder" "z:\destination_folder" transfer_this.txt /XF *.*

This command tells robocopy:

1. Copy from source_folder to destination_folder
2. Only include transfer_this.txt
3. Exclude all other files (*.*)

If you need to preserve all file attributes during the transfer, modify the command like this:

robocopy "c:\source_folder" "z:\destination_folder" transfer_this.txt /COPYALL /XF *.*

To rename the file during the copy operation, you'll need to combine the previous technique with a post-copy rename:

robocopy "c:\source_folder" "z:\destination_folder" transfer_this.txt /XF *.*
ren "z:\destination_folder\transfer_this.txt" "transferred.txt"

While this method works, it's worth noting that robocopy isn't the most efficient tool for single file transfers. For one-off file copies, consider these alternatives:

• copy "c:\transfer_this.txt" "z:\transferred.txt"
• xcopy "c:\transfer_this.txt" "z:\transferred.txt"
• PowerShell's Copy-Item cmdlet

Despite these limitations, robocopy remains superior for:

• Network transfers with automatic retry capability
• Preserving NTFS permissions and attributes
• Resuming interrupted transfers
• Generating detailed logs of operations

Here's a production-ready example that includes logging and verification:

robocopy "c:\source" "z:\backup" important_file.db /XF *.* /V /NP /LOG:C:\transfer_log.txt /TEE
if %ERRORLEVEL% LSS 8 (
    echo Success: File copied successfully
) else (
    echo Error: Transfer failed with error level %ERRORLEVEL%
)