I have searched the Dorico forums and do not seem to find the problem that I am experiencing, so I would like to let you know about it, in case it can help anyone else.
This is my situation. Completely new hardware (the key seemingly is Intel 7800X processor and the corresponding X299-based motherboard), but good old Windows 7 SP1 x64 Ultimate (and all Windows updates) installed, and the latest Dorico. I can launch Dorico to the Hub page, but trying to open existing Dorico files or trying to start from “New Empty Project” results in an unterminating hang (existing files stop at “60%” in the small progress bar). Dorico must be killed from the task manager (or sysinternal’s ProcessExplorer), as must its child process, VSTAudioEngine.
Attaching to the VSTAudioEngine process with a debugger (e.g., with MSVC++ 2010), with Dorico freshly opened and waiting at the Hub start page, then opening a file or starting a new project shows an uncaught exception:
'VSTAudioEngine.exe': Loaded 'F:\Program Files\Steinberg\Dorico\VSTAudioEngine\Vst3\VST Audio Engine Plug-in Set.vst3', Cannot find or open the PDB file First-chance exception at 0x0d978bc4 in VSTAudioEngine.exe: 0xC000001D: Illegal Instruction.
Details on a very similar (identical sounding crash from “illegal instruction”) crash running Cubase 9.x on my same hardware can be found here
where the problem has been noted in that thread as being an Intel problem that Steinberg developers are working on.
In the Cubase case, the problem comes during the execution of “Cubase Plug-in Set.vst3” (I’m not saying it is the cause, just that this vst3 module triggers the exception). Looking at Dorico, I found a similar vst3 module, “VST Audio Engine Plug-in Set.vst3”. If I remove this file (e.g., renaming the folder it is in), Dorico can open existing Dorico files and create new files from “New Empty Project”. (Of course, whatever built-in FX and/or instruments are in that vst3 module will not be available.)
I want to bring this to the Dorico team’s attention in case they are not yet aware of this problem and of the work being done on it by another team. Please take the following suggestion with the best intentions (mood/attitude are hard to judge over the internet; from one software engineer to another, I know things which may sound easy are often quite the opposite) that if possible, it might be good to incorporate similar exception catching code as used in “Cubase Plug-in Set.vst3” with either UI, an entry in VSTAudioEngine.log, or even a .dmp file, which could help in the future for problems which the user sees as a hang but could be an unhandled exception.