You may see this kind of alert if a Symantec product determined that the file has a "low reputation". This may happen especially for new versions that have just been released.
The downloaded file is quarantined or deleted immediately, preventing you from installing the software.
Please read this article on how to restore the file from quarantine:
Respond to incorrect Norton alerts that a file is infected or a program or website is suspicious
You can also submit the file to online virus scanners, where it will be checked by a number of different anti-virus products:
If possible, you can submit the file to your anti-virus vendor, so they will analyse and whitelist it if needed. Some even allow to do this in the warning notice (see "Details" or "More options", "Report false positive").
Download detected as WS.Reputation.1
Moderator: Fabrice