SyncBack does not scan for viruses. The error is from Windows stating that it (or whichever 3rd party anti-virus you have installed) believes the file contains a virus.
- If you do not have anti-virus software installed then you need to go to the Virus & threat protection section of Windows Security in Windows settings.
- If you do have anti-virus software installed then please refer to their documentation or contact their technical support for help in unblocking the file.
Note that you should not unblock the file unless you are certain that it does not contain a virus.