Good health to everybody!
I have noticed Avogadro2 1.90.0 cant’t open/save files from directory with non ASCII simbols:
C:\YandexDisk\Обучение\test.cml: Error while reading file
but C:\YandexDisk\Method_DM\test.cml is ok
Sorry for the slow reply. 
Huh. I thought we fixed this one back in Avogadro 1.0…
Does it work in older versions of Avogadro (e.g., 1.0.x)? If so, I can probably “bisect” to find the change that caused the bug to come back.
I have checked versions one more time.
Windows
Avogadro1 1.2.0 - ok
Avogadro2 1.90.0 - error
Rosa Fresh Linux:
Avogadro1 1.1.1 - error even saving at /home/rosa/
Great, I think I can get to that for the 1.91 release of Avogadro 2.