Well, I'm not sure that it's actually technically "hung"? Task manager shows that it's fine until I eventually try to right-click and "close" on the icon in the start bar, then it becomes unresponsive until I force quit it.
If I open a file in NP++, then the file is deleted or moved - I'm totally hosed. It prompts me with the "the file doesn't exist, do you want to keep it open" pop-up, but it won't allow me to do anything at all from then on. And I mean anything. I can't use my mouse to click on any part of the popup or the application window and have any impact whatsoever. Keyboard shortcuts don't do anything either. At best, I can go to task manager and try to bring the app to the foreground. But that's it. I can't even minimize/maximize via task manager. The only thing that I do is force quit the app. :(
This is not an issue if a file is updated while I have it open. I can say yes/no to that prompt without issues.
I have Windows 8.1 x64 and was running NP++ 5.2.8 or something. Upgraded to the latest - 6.5.5 this morning, but that didn't make a difference.
I like the file monitoring and don't want to disable it, but I will if I have to. This has happened at least 5 or 6 times now over the last 2-3 months? The first couple of times I lost a lot of unsaved notes, but I've now started saving everything, all the time, just in case.
I jyst tried that with the exact same configuration as you. No hanging at all, everything working as expected.
Is your file on a remote drive by any chance?
Are such plugins like Explorer or Light Explorer loaded?
Are some extra docked windows like FunctionList or DocumentMap open?
I'm experiencing the same problem on version 6.6.9, Windows 8.1 x64.