welcome to the notepad++ community, @MaxWattage
this is intriguing, and i hope we can work it out.
If Notepad++ is currently open, then [sometimes] Notepad++ won’t open, and nothing happens. (erratic/buggy behaviour)
This was tested on Windows 8.1 pro 64-bit
if notepad++ is in mono instance mode, and it is already open, it will not open another window, but it should always open your file.
can you check, if it makes any difference, whether the file to be opened, but does not open, has following conditions:
the file has spaces in it’s path or filename. the file is on a network drive and notepad++ is in administrator mode, which does not have access to the network drives mapped to your user account.also your debug info can be of help. please go to the notepad++ menu ? > debug info... > copy debug info into clipboard and paste the clipboard content here.
many thanks and best regards.