I keep hoping this will be noticeably improved, but Cubase is still quite slow to start up. It always has been in every past version compared to other DAWs on the same system such as Pro Tools, Reaper, and Studio One. Will this ever be at the level of DAWs like Studio One, Reaper, or even Pro Tools?
It makes a difference especially when Cubase can’t load up some very large projects back-to-back without crashing (a years-long issue on both Windows and Mac for others on the forum as well).
I must say I don’t have this issue - I wonder if it’s to do with the suites of plugins you use?
I am running a 2013 Mac Pro like you — though, I’m using Low Sierra — and Cubase 10 seems to load as quickly as 9.5 did. Other than my posting about the GUI using Audiobro’s Genesis Choir, I haven’t notice any difference in performance between Cubase 10 & 9.5.
So, to test out your loading issue, have you tried loading in Safe Mode? Or removed the plugins from your VST folder? Another thing others have mentioned, moving your C9.5 preferences out of User>Library>Preferences folder since C10 just copies over the prefs from 9.5.
Or, try creating a new user in macOS and load Cubase there?
Would you happen to have a lot of Steinberg instruments or loops or effects loading with Cubase? I know C10 came with more content so could that possibly be causing the longer load time?
Anyway, not saying you’re incorrect — just seeing if it’s something that’s easily remedied. 
I tried your suggestions Bender-Offender, and it stayed the same unfortunately. It was the same in C9.5 – it’s always been slower than the others. And I even did did a complete re-install of Mojave from scratch before I installed C10.
Compared to Pro Tools, Reaper, and Studio One on my system, Cubase is noticeably the slowest to start, and it shares the exact same VST folders as Reaper and Studio One.
It lags on “Initializing”, but there’s nothing in the readout that it’s initializing when it lags. It doesn’t lag when it shows something it’s initializing. Again: Brand new install of Mojave and C10, nothing else on the Mac.
From the time I hit the C10 icon to the time it actually starts it’s 36 secs (just timed it). Bad news. If it’s plugins then it’s Cubase’s issue because the exact same VST plugin folders are with Reaper and Studio One and they both load up very fast (especially Reaper, but they’re very far ahead of the rest of the DAW world in ways like that).
Yes, starting Cubase is slow. Has been slow since I came aboard(Cubase Pro 8.0). At least 30 seconds.
Compare this to Logic Pro, starts in 1 second or so.
Also Live, Reaper, Waveform etc. all boot much faster.
It’s not a big deal, but when I want to try out something really fast I start Logic instead of Cubase.
I also have that feeling, that something’s not 100% right when loading the projects. Especially projects with more than 30 tracks have some “delay”. Rendering the track so that there is nothing to load from the instrument didn’t help in my case. On the same track there is a waiting time… and often the project loading freezes.
Dear all
I solved all my problems by updating Windows 10 to the October-Release 1809. That update was not automatically pushed to my system. Now everything works fine for me. No crashes anymore and fast as hell.
So you have a very fast Cubase startup time that’s comparable to other DAWs? If so, that’s great – but for us Mac users we’re still stuck with a very slow startup time.