This has been around since for ever, now it's a 4kb file. Where did MS decide to stash all the icons? I use them when illustrating user manuals and this is a big deal not having access.

1 Answer 1


In earlier Windows builds, icon resource files were embedded in some DLL in the directory C:\Windows\System32. Since Windows 10 version 1903, they have been relocated to: C:\Windows\SystemResources.

There is now a new extension for these files .mun instead of .mui (which still exist in system32 and syswow64 sub folders.

Specifically, imageres.dll is now found in C:\Windows\SystemResources\imageres.dll.mun.

You now can edit icons from SystemResources more easily, as there are no digital signatures to worry about or syswow64 and system32 files to edit. There are still some files in system32 that contain icons, but most have been relocated.

  • 1
    Thanks, that's exactly it. To use an icon extractor I copied it to the desktop, removed the .mun extension and it worked. So it's basically a DLL with a new extension appended.
    – SKidd
    Sep 9, 2019 at 13:01
  • I was able to directly drag and drop the .mun files from the SystemResources folder into my icon editor and extract the icons. Apr 10, 2020 at 19:21

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