It doesn't require to remove one to install other.
Could you share with us some error message or screen snap shot to let us know what happened with KIT-042-BLE on PSoC Creator 4.1?
I was previously not able to install both 4.1 and 4.2 in the "complete" installation mode but after the post was able to add 4.2 in "typical" to 4.1 previously installed as "complete". I was then able to install the kit with both creators closed. When I opened 4.2 it was shown installed and could access. When I closed 4.2 and opened 4.1, the kit was listed but greyed out and shown as "Incompatible with current PSoC Creator. Version '188.8.131.521' or higher required". See attached screenshot from 4.1 .
PSoC 03.jpg 279.7 K
Still having problems with installing CY8CKIT-042-BLE in 4.2. See previous post. Please send link to an archive with the files for this kit that are compatible with 4.1
As alternative, you can download the Kit "example projects", "Hardware Design Files" and documents from the kit webpage, for example CY8CKIT-042-BLE-A:
After install the kit installation program the installed stuffs(Default path: C:\Program Files (x86)\Cypress\CY8CKIT-042-BLE-A Kit\1.0) is nothing but these files.
Download CY8CKIT-042-BLE-A Example Projects.zip English 809.77 KB 06/18/2018 CY8CKIT-042-BLE_A_Board_Design_Files(Schematic,Layout,Gerber,BOM).zip English 6.66 MB 06/18/2018 CY8CKIT-042-BLE-A Bluetooth® Low Energy Pioneer Kit Release Notes.pdf English 167.19 KB 06/18/2018 CY8CKIT-042-BLE-A Quick Start Guide.pdf English 4.91 MB 06/18/2018 BLE 4.2 Dongle CySmart 184.108.40.206.hex (PSoC BLE Dongle).hex English 564.47 KB 06/18/2018 CY8CKIT-042-BLE-A Bluetooth® Low Energy (BLE) Pioneer Kit Guide.pdf English 7.78 MB 06/04/2018