When I had performed the latest virus scan with AVAST, “ZIPPER-2778” virus has been detected in a backup file, saved on an external hard drive. This backup had been performed two months before, with Windows backup & restore utility program. During this time, my computer ran quite OK.
However, the C:\ drive virus scan don’t show any problem. Only the backup file is infected !
Intending to eradicate this virus, I’ve formatted the external hard drive, and then restart another backup of C:\ drive with Windows utility program. As before, the backup file is saved on external hard drive F:
Just later, I ran the virus scan on drives C:\ and F:\ with AVAST program.
“Zipper-2778” virus came out again, only in backup file, on F:. On the contrary, C:\ drive is free of all known viruses.
Have you an explanation ? Is this case a false positive ?
Thanks in advance.