I have received the same message but didn't know to look for it until I read your post.  Work has been running CC 2018 on Windows 7 (64).  Premiere has been running slow for a few months now, since the 2017 CC release I believe.  4k footage could not be viewed properly without rendering PROXY files.  After Effects had problems rending as well.  Encoder would take an hour for a non-graphic heavy 30 second ad.  Also, Adobe was not using all the CPU when it was working either on a render or an export.   When we were doing some research we discovered  Adobe has not supported Windows 7 since the CC 2015 update.  Many on the internet suggest if you are sticking to Windows 7 back install your Adobe to CC 2015.  Monday our IT department switch us to Windows 10.  As a computer user, Windows 10 has a its own unbearable intricacies.  However, every issue listed above was fixed by updating the OS.  I don't know what kind of money Windows is putting into Adobe to force all its user to update the OS just to use the newest Adobe updates.  If you are having no troubles, continue as you are. Just be aware there will be no other updates available to you from CC on your Windows 7 computer.  If you are having issues, downgrade to CC 2015 or upgrade the OS.  ... View more