Transferring files between local machines and EC2 Windows instances presents unique security considerations while requiring efficient data movement. Unlike traditional physical servers, EC2 instances operate within AWS's virtualized environment, necessitating specific transfer protocols.

The simplest approach leverages built-in RDP functionality. After establishing your RDP connection:

1. Launch Remote Desktop Connection (mstsc.exe)
2. Click "Show Options" → "Local Resources" tab
3. Under "More..." button, select drives to share

# PowerShell command to verify RDP sharing
Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server' -Name 'fDisableClip'

For environments where RDP isn't allowed or practical:

# Install AWS CLI and SSM plugin first
aws ssm send-command \
    --instance-id "i-1234567890abcdef0" \
    --document-name "AWS-RunPowerShellScript" \
    --parameters '{"commands":["Invoke-WebRequest -Uri https://example.com/file.zip -OutFile C:\\temp\\file.zip"]}'

This method works well for automated deployments and CI/CD pipelines.

A robust enterprise solution pattern:

1. Upload files to S3 from local machine
2. Attach IAM role with S3 read permissions to EC2 instance
3. Use AWS Tools for PowerShell on the instance

# S3 transfer commands
Read-S3Object -BucketName my-bucket -Key folder/file.txt -File C:\destination\file.txt

Always:

• Use VPC endpoints for S3 when possible
• Set appropriate bucket policies
• Enable S3 server access logging
• Consider temporary credentials for one-time transfers

For RDP file transfer failures:

# Check RDP file sharing registry settings
reg query "HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server" /v fDisableClip

Common resolution paths include checking security group rules for port 3389 and verifying instance storage availability.

Before transferring files to your EC2 Windows instance, ensure you have:

• Administrative access to the EC2 instance
• RDP client installed on your local machine
• Proper security group rules allowing RDP (port 3389) and optionally SMB (port 445)
• The instance's public DNS or IP address
• Your .pem key pair file (for initial setup)

The simplest way for Windows-to-Windows transfer:

1. Connect to your instance via RDP
2. During connection setup, click "Show Options"
3. Navigate to the "Local Resources" tab
4. Click "More..." under "Local devices and resources"
5. Expand "Drives" and select the local drives you want to access
6. Complete the RDP connection
7. In the EC2 instance, open File Explorer - your local drives will appear under "This PC"

For larger or automated transfers:

# First, enable file sharing on your EC2 instance:
1. Open Server Manager
2. Add the "File and Storage Services" role
3. Create a shared folder with appropriate permissions

# Then from your local machine:
net use Z: \\ec2-public-dns\sharename /user:Administrator password

For secure transfers without opening ports:

# Install AWS CLI and SSM plugin first
aws ssm start-session --target instance-id

# Use AWS-StartPortForwardingSession to forward SMB
aws ssm start-session --target i-1234567890abcdef0 \
--document-name AWS-StartPortForwardingSession \
--parameters '{"portNumber":["445"],"localPortNumber":["445"]}'

For programmatic transfers:

# Upload from local to S3
aws s3 cp local_file.txt s3://my-bucket/

# Then on EC2 instance
aws s3 cp s3://my-bucket/local_file.txt C:\destination\

If you encounter problems:

• Check security group rules for open ports
• Verify Windows Firewall settings on the EC2 instance
• Ensure the EC2 instance has outbound internet access
• For RDP drive redirection, confirm your RDP client supports it