If you receive the error in your backup logs: "Backup Failed : C:\$Windows.~BT\xx Error e0010012: Client file is busy, retry" points to Windows 10 pre-install files that Microsoft has pushed to your PC; Microsoft has pushed pre-install files to the C:\$Windows.~BT\ folder which is a PROTECTED FOLDER that cannot be backed up. Since NovaBACKUP by default backs up any new folder on your computer, unless you tell it to exclude specific folder(s) or de-select specific folders then it will attempt to back up that newly created folder as standard.
There are certain folders which cannot be included in your file backup including a new folder that was first discovered August 1 2015; this is a folder which Microsoft has pushed to your PC, the folder is named "C:\$Windows.~BT\". This folder "C:\$Windows.~BT\" has to do with the Windows 10 downloaded files which cannot be backed up since that is a protected folder which will deny access to back up. There are two methods to remove this folder from your backup selection to avoid the error(s) seen in the logs. The easiest and recommended first method to accomplish this, without having to edit each of your file backup jobs like the second method requires you to do, is to simply exclude the "$Windows.~BT\" folder from NovaBACKUP software so that it could never be selected for or attempted to be backed up. You can do this by loading NovaBACKUP and clicking on the large circle NovaStor logo button at the top left of the application, then go to Default Settings -> Advanced Options -> click on "Edit default exclude filter" -> The notepad program will open up with a text file "nexc.ini", simply change the line under [exclude] from path.numberOfItems=13 to 14 and then add this line at the bottom as "path.item.13=?:\$Windows.~BT". Follow the example below for how your "nsexc.ini" text file should look
The example would look like this, the changes that you are making here are highlighted in bold, you will be making two changes:
path.item.12=?:\System Volume Information
Once done editing the file you will save it by clicking File menu and then Save and then exit notepad, or you can simply try closing the text file and it will prompt you to save if you have not. Then click OK at the bottom of the screen in NovaBACKUP's Advanced Options screen and you are done.
The first method will affect ALL of your file backup jobs without you editing them. The second method to use in order to NOT see these errors in your backup logs you would need to edit each of your file level backup jobs (those jobs created in the "Backup" tab or "Express Wizard" and remove that particular root folder (C:\$Windows.~BT\") from the selection set by un-checking the check box to the left of the folder at the top of the list named "C:\$Windows.~BT\". Then save the job. Now that folder will not be attempted to back up. Only if you utilized the second method, then you will have to make this same change to all of your file backup jobs.
"Backup Failed : C:\$Windows.~BT\Sources\SafeOS\SafeOS.Mount\Program Files\desktop.ini Error e0010012: Client file is busy, retry"
Here are articles on a Google.com search for this issue with this particular folder:
NOTE: Official support for Windows 10 was added in NovaBACKUP v17.1.804, only that version and above would support Windows 10.