d3dx9_39.dll missing

Question

I am trying to play League of Legends on my Surface Pro 3, however the game client will prompt me with the message, "The program can't start because d3dx9_39.dll is missing from your computer. Try reinstalling the program to fix this problem." I tried reinstalling League of Legends, but that did not help. I also tried to install the d3dx9_39 manually from the internet, and putting the 64 bit and 32 bit into my C drive in folders SysWOW64 and System 32, respectively. Unfortunately this also did no work. I did a little bit of research online about updating my directx, but I checked it in the dxdiag program, and I do have the most recent version - DirectX 12. Is there anything that I can do to fix my issue?

Answer 1

Hi Gidon

Please see the solution posted to the League of Legends forum to see if that resolves this for you . . .

https://boards.na.leagueoflegends.com/en/c/help...

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Answer 2

There has been a problem for quite some time with corrupted .NET causing DX errors such as yours which starts with an 

error from a game and persists when trying to reinstall DirectX using the DX Redist installer, or when running the DX Web Installer.

This may apply to your issue as well. Try repairing .NET.

https://docs.microsoft.com/en-us/dotnet/framework/install/repair

btw ...

"dxdiag program, and I do have the most recent version - DirectX 12. Is there anything that I can do to fix my issue? "

• The main page in dxdiag only shows the highest level DX Win10 is capable of using, not if you have the 'latest' DX12 files,

or if your graphics processor is capable of running DX12 games. For this you need to look in dxdiag - Display tab > Feature Levels.

There is no need, and it is not advisable, to download .dll files from the various .dll download sites as there is good potential for

extras that may come with the file, eg- spyware, addware, and other PUP's .

There have been no new versions of DX 12 as of yet, and the last DX9,10 & 11 updates were released in June 2010. These are in

the -  DirectX Redist (June 2010)  - along with all of the earlier DX9,10 & 11 files.

The  DirectX Web Installer  will install any missing files, but it cannot repair corrupt files as can the full installer package.