Thanks for contacting us.
To help you better, please tell us which edition of our product you are using, what is the version number?
To solve the lock issue, we hope you can have a try to connect the disk to another machine as slave disk, then go to the original C partition to locate and delete the file "EPMBatch.ept" under Windows folder if it exists. After that, please connect the system disk back and boot from it. Then tell us the result.
And we want to remind you that file is hidden by default. So, please open 'My Computer', then choose 'Tools\Folder Options', Turn to 'View' page, check on 'Show hidden files and folders', uncheck 'Hide protected operating system files(Recommended)'. Then click "OK".
By the way, if you are paid user of EaseUS Partition Master, and the current version number is not 9.2.1, then please refer to the following link to upgrade to this latest version to manage partitions on Windows 8, as version 9.2.1 can support Windows 8 better.
Here is the link:http://kb.easeus.com/art.php?id=20004