If the whole Vault would be encrypted by the virus already, you can do a revision restore for the whole vault to a previous point in time.
Before restoring any data, make sure that the infected PC isn't syncing anymore and that the virus is removed.
- log in at myNomadesk.com and select the Vault that you want to restore
- make a new restore folder on the Vault (you can choose any name). The whole Vault will be restored in that folder
- go to revisions, right click on the Vault name under Filename and select restore
- select a date and time for the restore
- select the folder that you created for the restore and click restore
- in the bottom of the screen you'll see the status of the restore. Do keep in mind that if it is a large Vault the restore will take some time. Once it is done you'll see a green checkmark that everything is OK
- next you can move the restored data back to the original location and deleted any encrypted files still present on your Vault.