Broken icon for txt files

Windows 10 Pro 22H2

UPDATE: I forgot to mention in my post that I'm using the portable version of Npp. So I decided to install the standard version, then uninstalled it using the option to delete settings files. Then I re-associated txt files with my portable version and the icon is fixed!!!!! I'm going to make this thread as solved.

I use Notepad++ (Npp) as my default text editor and a few days ago the Npp icon for txt files broke. I can’t be 100% sure but I think it happened when I uninstalled a version of Microsoft Office 2013. After that I noticed icons for txt, docx, and xlsx files were broken (maybe other Office file icons too but I didn’t check them) and, as far as I’m aware, the txt icons were fine before that. When I reinstalled Office, the icons for docx and xlsx came back but not txt. All the other file types I have associated with Npp still have the Npp icon but, for txt files, all I get now is the default ‘unknown’ file type, plain white icon. Text files still open using Npp.

Things I’ve tried:
I changed the default program for txt files (via Windows Settings > Choose default applications by file type) to Notepad and Wordpad to check if the icons display for those and they do. When I changed it back to Npp the icon is still broken.
I reset the Windows icon cache by deleting iconcache.db from my system then restarted Windows Explorer. That made no difference, so I also restarted my PC.
I used two third-party apps (Default Programs Editor and FileTypesMan) to change the icon to something completely different to one from notepad++.exe.

I know I can check/edit/delete entries in the registry but I’m not sure which would be causing this issue. I did look here and the icon setting is correct: HKEY_CLASSES_ROOT\Notepad++_file\DefaultIcon

Notepad++ file association (set as default app) is done within the app.

How to Replace Notepad with Notepad++ in Windows 10

Also if you want it to always run in place of notepad you can use Image File Execution Options and set it as debugger.

How to always launch Notepad++ in place of Notepad

This is useful for example when using things like some hosts file editors and maybe other apps that might launch notepad by default.

Note: I don't use Notepad++ but have used it in the past.

Your delete iconcache.db method won't work. You have to terminate explorer and delete all of them.

See:

Rebuild Icon Cache in Windows 10

You can set the icon for any file type you wish using this free utility (and quite a bit more):

Anyway also see Notepad Replacement here:

Other Resources | Notepad++ User Manual

The IFEO option always works but it won't show as set the default app in set default programs and it won't change the icon for the default app that is already set. It will just always launch Notepad++ in place of Notepad.

As that didn't work, it sounds like something's damaged in your registry.

Start by resetting the association to default for txt using this tutorial, from the huge searchable Tutorials section:
Restore Default File Type Associations in Windows 10

You will then need to reassociate txt as you prefer.