Hi,
Thank you for sharing your question. Dealing with error 0x80071772 can be super annoying, mainly when you're just trying to get into some files. This happens because the file you're trying to open is encrypted with Encrypting File System (EFS), and Windows says your account doesn't have the right key or permission to open it.
If someone else encrypted the file, or it was encrypted on a different computer, your account probably can't access the EFS certificate that was used. So, Windows won't let you open it.
Here's how to fix it
First, see if the person who encrypted the file can either decrypt it for you or give you their EFS certificate and key. If that doesn't work, you'll need someone setup as a recovery agent in your domain to decrypt the file.
If you encrypted the file on another computer, get the EFS certificate and private key from that computer (use the Certificates thingy under Personal → Certificates) and then put it on your current machine. After you do that, Windows should be able to decrypt the file.
Once you've moved the certificate, try opening the file again. Windows should automatically use the key and let you open the file without that 0x80071772 error.
I hope this helps.
Best Regards,
Noel