How to open a big file in Notepad++?

Notepad++ doesn't support huge files, according to this wiki documentation, the problem persists if the component (Scintilla) remains as the core of Notepad++ :

Older versions of Notepad++ may crash while opening very large files. Newer versions (5.2+) will deny opening the file and issue an error message. Why is that?

Notepad++ is based on a component (Scintilla) which is geared towards providing rich text viewing, with syntax highlighting and code folding, as opposed to bulk text services. There are necessary trade offs. Loading a 200MB file will require around 800MB of memory, and the OS may balk at the memory allocation request.

There are basically two ways out:

• Split the huge file into manageable chunks, and keep only one of them in editor;
• Use another tool which is tailored to handle massive text files.

If you still manage to open a large file, performance may not be optimal. Here is a couple things to think about:

• Plugins which analyse and scan text will slow down NP++, disable them if possible
• Parsing for clickable links on loading the document is slow if the document is large; disabling the clickable links has been reported to significantly help.

Another page on sourceforge also suggests that this problem persists throughout Notepad++'s life, as the community requested to solve this problem:

Why don't you try other software such as gVim? Is there any reason?

Syntax highlighting is one of the main sources of slow performance in Notepad++.

If you're opening a massive HTML, PHP, etc file in Notepad++, then you'll probably want to disable the syntax highlighting for that file by going to Language > N > Normal Text.

You should also disable clickable links by going to Settings > Preferences > MISC. > Clickable Link Settings and unchecking the Enable checkbox.