There is no problem in running both HLS and LDK on the same computer. If you have licenses for both installed you can even run RIPs using both concurrently.
It is not recommended to try to run the same RIP installation, switching between HLS and LDK, but if you absolutely need to test in that way you can use a single RIP installation and switch between the two by amending the second line of the \SW\secprefs file between ldk and hls.
Note, however, that:
- The HLS and LDK licenses will probably provide different RIP serial numbers, so that any encrypted fonts, screen caches or plugins that are secured against the serial number may not work as expected in both.
- Running the RIP with LDK will delete the HLS passwords; you will have to re‐enable options, plugins and so on, the next time you start it with HLS.
- You will need to have installed all runtime components for both HLS and LDK. The easiest way to do this is to install two RIPs; one using HLS and the other using LDK.