Hello.
When I close the Steinberg Hub window, the window closes and a message box appears. There is no such error with any other applications.
My OS Win7 x64
Are any .dmp files saved on your computer when Dorico crashes? Please have a look in %SYSTEMROOT%\minidump to see if any crash dump files are found there, and zip them up and attach them here.
I would also recommend that you try updating your audio drivers, in case they are the cause of instability.
Thank you for your answer, but unfortunately it did not help. There are no dumps of the errors. Drivers for my sound cards have the latest: RME UFX and a Focusrite Saffire Pro 40. The error occurs when working with any sound card. It seems that everything works: files are opened and saved, but still the error is alarming.
I’m sorry that I don’t have any other suggestions at the moment. Dorico is not officially supported on Windows 7, though as you’ve found it does work on that OS version. Provided you’re finding that Dorico itself is stable except for when quitting the application, hopefully you’ll be OK.
The fact that you do not support Win7 is in vain, because I know a lot of professional composers and arrangers who work in Win7, and do not intend to switch to Win10. Why upgrade if everything works? However, another answer from you I not expected. Excuse… 
Thank.
Well they may not wish to change to win 10 but version 7 hasn’t had mainstream support since 2015. New programs like Dorico really can’t be expected to add workarounds so as to support an OS which essentially will not fix or update any flaws which show up when new programs prove incompatible. It’s fine if your current programs run but you can’t use an OS forever if you want to use new applications.
That’s understandable. But there are no fundamental differences, because all the same programs run in the same runtime environment. I have an OS setup very different from the typical one, and I’m sure on Win 10 (with the same configuration) I would have the same error. Probably Steinberg Hub when closing something wants to write, and nowhere or prohibited. OK, Dorico works well, and the fact that I have an error when closing Steinberg Hub is nothing.
aveter,
I hope I can be forgiven for asking the obvious: what do the two messages in your OP actually say, please?
Those two pngs appear as Russian for me.
Since there are some differences how Windows 10 treats file permissions compared to Windows 7, I would think that the error really might come from Windows 7 vs. Windows 10.