When i use LoadANSITextFileToString cyrillic symbols transforms to ???.
There is another way to load text file with cyrillic symbols from directrory?
UE4 has never been good at handling Cyrillic symbols, so I doubt you will be able to open that file. If you have a cyrillic symbol in a folder name for a project the editor can end up crashing.
EDIT: You can also try converting those characters to their digit code and then using an alternate function to load them in, such as unicode:
http://jrgraphix.net/r/Unicode/0400-04FF
Here’s some info from the Docs
.unrealengine.com/en-us/Programming/UnrealArchitecture/StringHandling/CharacterEncoding