You can try WiseRecovery which has solved the same problem for me some days ago. When searching on the Internet and find a web page which produced WiseRecovery. I have no idea about I should try WiseRecovery.However WiseRecovery helped me a lot. You can have a try.
1. Download WiseRecovery Software, install it and launch it. Click the "Start Scan" button on the main window of WiseRecovery.
2. You can see the list of all volumes found on your computer, select the exact drive and click the "Next" button to start scanning. If you can't see the drive, please make sure your external drives are connected, and click 'Refresh' button.
3. It will take about 2-10 minutes to scan, it depends on your disk size and files amount on the disk. After scanning is finished, you can preview text document and files.