As detailed in the other forum (https://www.vsl.co.at/community/posts/m269814-macOS-High-Sierra--10-13--compatibility#post269814) the solution that involves deleting the com.motu.MotuAudioSystem folder and 'renaming' your vst folder and such DOES actually work, however it is incorrect. (http://www.motunation.com/forum/viewtopic.php?f=1&t=64443)
1) You must go to com.motu.MotuAudioSystem folder and delete the Audio Unit and VST Info Cache files EVERY TIME after you have closed out of DP. If you've customized which plugins you're loading, especially VST's (see below) then do NOT erase the Audio Plugin Prefs file. This means that yes, you must reload them upon opening DP, but it also means that YOU CAN USE YOUR VST PLUGINS! (see #2)
2) You DO NOT have to rename the VST folder, and as such you can use your VST's (at least after you've done the steps. You can go back, rename the folder, and then have DP examine the VST's). However, I would in the preferences refrain from loading VST VEP. You have AU and MAS that will work via this method, and I'm too lazy to test if it works (it probably does). I'd also suggest only having it examine the VST plugins you actually use, because while the AU ones are fast, the VST's take significantly longer. If you only use VST's as eq, compression, and virtual space, for instance, you can do all of that in VEP so...a strange work around but yah.
3) I have tried the above method of deleting the .bundle files for VEP. Did not affect this method at all, except that I wasnt able to use the MAS versions of VEP. Hey, with the above method, you can use the MAS VEP.
I highly suspect this glitch has to do with how DP analyzes plugins the first time around and then creates an info cache. Since deleting the cache fixes the problem until DP is restarted, I'm honestly not sure why a simple programing fix involving those plugins cant be done on MOTU's side. There, I'm finally pointing the finger at the software company with the real problem, and they have done little about it except pointing fingers at everyone else. I'm not losing any money on this issue yet, but for any of you who are, I think this is probably grounds for a lawsuit. Feel free to lawyer up!
I hope this helps. Maybe its a system by system problem and theres a billion different solutions for this issue and all of you are right, but this one worked for me.