If you want to remain the Illustrator CC-CC2017 which is installed in your personal computer when updating to Illustrator CC2018, update with the following procedure. (Also FineCut/RasterLinkTools which is installed in your personal computer will be remained.)
[Procedure 1]
Click [Update All] or [Update] button at right side of Illustrator CC.
[Procedure 2]
Click [Advanced Options] button.
[Procedure 3]
Switch off [Remove old versions] of [Advanced Options] checkbox, and click [Update] button.
![](https://d2w577gk9zpoty.cloudfront.net/archives/126/201710/3f0e73e27e91bbcb07728571a397ea9a.jpg)