Unable to download Norton antivirus on my iMac

most people here posting about norton are asking how to uninstall it

How to uninstall Norton Anti-Virus Softwa… - Apple Community

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all third party virus scanners does in this day and age is to slow down computers, the build in protections of both macos and windows is fine.

First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac.  This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.  

There are no known viruses, i.e. self propagating, for Macs.  There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.   

Anti Virus developers try to group all types as viruses into their ad campaigns of fear.  They do a poor job of the detecting and isolating the adware and malware.  Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.

There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it.  The free version is more than adequate for most users.  

Unless you're using a true VPN tunnel, such as between you and your employer's, school's or bank's servers, they provide false security from a privacy standpoint.  Read these two articles: Public VPN's are anything but private and Security Risks: The Dangers of Using Free VPNs (eccu.edu)

Not only is "Norton" a horrible product to install on a Mac, its relationship to "LogMeIn Rescue" is dubious at best.

https://www.logmeinrescue.com/

There is nothing wrong with LogMeIn but I would be extremely circumspect about installing anything that also wants to install remote access software as a required component. That's a red flag, at best.

Do not install "Norton". Rule 1 of Macs is don't install junk.

More information may help. I have no idea whether "Norton" is dependent upon "LogMeIn" or not, but something isn't right. Did you install that product in the past? Is it possible that it was installed by someone else, perhaps with malicious intent?

+5

Don’t do it. Norton is garbage and will do nothing but cause problems on your Mac.

+10

(Do I hear 15?) 🙂