A report was received about issues when using Extended Characters in filenames (for example, Turkish characters in filenames).
Comparison is performed fine, but when a Copy action is requested, the copy may fail when using extended characters in filenames.
Comparator Fast uses Windows services to process Copy/Move file actions, this means, if you can Copy with Windows Explorer, you should copy a file with Comparator Fast.
If you found problems when using Extended Characters in filenames, please set the default language on Regional Settings (Control Panel):

For this case, when using Turkish characters on filenames, you need to add Turkish language support.
Thanks to I.K.
Daniel