Firefox won't download - "the source file could not be read" error

To know if it is an issue between NOD32 is to temporarily uninstall it. Uninstalling won’t usually remove license information or the uninstaller may if you want to keep that along with files in quarantine.

Please attach a diagnostics report.

main interface window > question mark (?) > support > diagnostics

As there has been no response, I will move this issue to “Resolved” section.

Thanks.