Note:  the second link in the post above is to a third-party website.  Be very careful before uploading information to it - it is suspect in its veracity and could easily expose you to data loss or identity theft.
VHD files are prone to corruption just like any other computer file. There are various reasons which can cause corruption in VHD files and make them inaccessible. Thankfully, Microsoft provides VHD tool that can fix corrupt VHD file and recover data from it. Also, there are a couple of manual tricks you can try here to repair VHD file.  The above information has been taken from this source - Repair VHD File Manually – Utmost Solutions for VHD Recovery Before you can purchase any paid software, you must try the VHD tool (provided by Microsoft) and the manual tricks shared in the above article. I hope the shared information would be helpful here.  Thanks and best regards.
How to repair VHD file?