Kaspersky Internet Security Requires an Update for Windows 10
If you are using Kaspersky Internet Security, you need to go to their web site and download the version that works with Windows 10. If you don’t, you won’t get a warning, but it does not work after the upgrade! I found out on my own machine. This may be true of many applications, though, it is a good idea to make sure that you upgrade all your apps after you upgrade to Windows 10.