Greywolf1: I also doubt that disabling your antivirus system, even temporarily, is going to help. I have seen this advice so often, but never seen any indication that it actually did help.
Then you haven't bothered to look, or you would have found literally thousands of examples.
Simply Google antivirus software block Directx 9, click on any youtube video that explains the problem and see how many times he/she has been thanked for posting it.
Greywolf1: I myself would never disable MY antivirus system to solve a problem - either there is a different solution,
If your antivirus is the cause of the problem, then disabling it is the solution.
Greywolf1: or the system which can't coexist with my antivirus system is likely to do something which my antivirus system is trying to protect me against, and is thus unsafe and a risk for my PC.
Your antivirus software has never found a virus in any file on the Microsoft website.
If there ever was one, 100 million plus users would be up in arms about it instantly and you would know.
Even in blocking the old DLL's, the antivirus software never claim to have found a threat in them.
They block them solely on the grounds they are old DLL's and a potential threat.
But old games need old DirectX files to run properly.
It's why they are included when you get the game from Steam, GOG, or from the retail disks.
The game specifies DirectX 9.0c or later, because at that time new DirectX versions had always been backwards compatible with previous versions. But in order to advance their DirectX-Box or X-Box they had to abandon full backwards compatibility to move forward.
Windows 10 has DirectX embedded into the operating system, but it is only fully compatible back as far as DirectX 9.11.
If the automated setup files you get from Steam or GOG try to install the necessary version, the antivirus program can and often do stop the older .dll's from being registered with the operating system, and give you no warning that everything wasn't installed as intended.
You only know when the game crashes or won't start at all.
Happened to me with AVG and GOG's Neverwinter Nights 2, I spent days trying to locate the source of the crashing before checking in the event viewer showed AVG had block DirectX at the time I installed the game.
A quick Google will show that is is not just AVG, but many, if not all antvirus software has done this at one stage or another, going back years and it still happens.
Some games, like the Witcher will check the registry for the specific version they need and give an error message if it is not there when you try to start the game.
Given that all versions of the Witcher come with the correct DirectX version, the only reason it wouldn't be there is if your antivirus stopped it at installation.
So your antivirus software isn't keeping you safe by blocking these old Microsoft files, because no one ever got a virus from them.
They are simply stopping you from installing what you want and need to install.
It may not be the problem in this case, but it happens a lot and only takes a few minutes to try.
Don't worry about viruses in any files you get from Microsoft, their internet security is like Fort Knox.
Unlike Steam, who's internet security has been breached on at least 2 occasions that I'm aware of.
People who tell you not to trust Microsoft and then link you to the Nexus to get mod files, when the Nexus has had their internet security breached in the past and user details and passwords compromised.
I never asked the OP to disable his antivirus software before downloading the SDK.
By all means, have you background checker scan it before download, and if your paranoid right click on it after it is downloaded an manually check it again. You won't find anything though, there is probably no safer site on the net.