Just download the KTS 2021 version installer (online) from the Kaspersky website[2.71 MB].
Run the installer, remove incompatible software, complete the installation process, and restart your PC.
Launch KTS 2021, and activate with the below license code. 3M3K9-5R92S-ZDH5Y-NA944
In my opinion, compared to some other AVs (Norton being much worse, actually), it's a real pain trying to keep a whitelist/keep whitelisted a large number of programs Kaspersky isn't a fan of.
I'm actually having another go with it at the moment for different reasons, and it's ok, but still far too many menus to wade through to exclude something, and arguably not enough information given about where and one to reverse a blocked program.
My analogy points to the fact that Kaspersky is well made and doing its job, and you can take control over it with some effort (I turned the firewall off for starters). Norton360 was insulting junk, though. That program would frequently and untraceably break things on my system without a log of any kind to refer to. Kaspersky does have a log which, although a bit hidden, usually gives you a yay or nay as to its culpability when something goes awry.