External Hard Drive decrypted by Spora Ransomware

Hello,

I have an external hard disc that was infected with the Spora Ransomware when it was connected to my laptop.

Initially, I right click on the hard disc folder, properties > previous versions. I found a restore point a few days ago and was able to access the files inside it. I proceeded to copy all the files and paste it into another new external hard disc. However suddenly the transfer just stopped, and when I click on the previous versions now, there are no more restore points available.

Does anybody have any idea why the restore points have disappeared, and how it can re-appear so I can back up these important information? Thanks.