Remove the drive. Hook it up as a data drive.
Click on your My Computer icon on your desktop.
Identify the compressed drive. Depending on your system, the compressed drive might display in a text color other than black.
Right click on the compressed drive and choose Properties from the given options.
Click on the box next to the text line Compress drive to save disk space. This will remove the check mark in the box.
Click the Apply button at the bottom of the screen.
Choose between uncompressing the entire drive or uncompressing the files and folders by clicking the radio button next to your choice. Click OK. Compression will be removed from the drive.