I am on version 6.6.9. When I do a file search on a large directory (wordpress) for a particular phrase, It will complete search, but input to a file is frozen and notepad says it has errors. Using windows task manager to close notepad in the only way to clear the program from windows. The windows close button does not function. As a side (possibly) issue, having an option to skip image files and binaries when doing file searches would be very useful. Task manager sometimes will have subprocesses left open with some sort of file open/access issue (I just have the title to go with).
You should post such reports in the Tickets/Bugs section.
This patch:
https://sourceforge.net/p/notepad-plus/patches/627/
fixes the issue.
wrong checker