How to copy or replace DLLs from your GAC

If you want to actually browse DLLs in your GAC at C:\Windows\assembly\ follow the instructions below.  This register edit will disable the assembly viewer and instead let you browse files like you would any other folder and allow you to grab or copy files, etc.

1)    Use Regedit and go to HKLM\SOFTWARE\Microsoft\Fusion and add a REG_DWORD entry called “DisableCacheViewer” and set the value to 1

2)    After updating that entry you can path through to C:\Windows\assembly\ and copy or grab files, replace them, etc. 

WARNING: Always be careful and backup files before you replace them.  Also, make sure you hit CTRL+C to copy a file as dragging and dropping may actually move the file out of the folder.

Comments (5)

  1. Charles says:

    I have no idea what you just said. You are adding to my frustration.

    I cant even find the HKLM to start with.

  2. Mohammed says:


  3. Jan says:

    Nice post and yes… I have an idea what you said.

  4. Jan says:

    FYI: as of Windows 8 this registry key is no longer supported. Windows 8 uses standard File Explorer to view C:WindowsAssemblies and not Assembly Viewer. Yes, I am working on a project involving the GAC on Windows 7 and 8 so my renewed interest in this flag.

  5. jag says:

    Guys – this does not work in windows 8/10 – any ideas

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