Hello, I am trying to run an older application that requires the fast2001.ocx

: You are trying to run an older 32-bit application on a modern 64-bit version of Windows (like Windows 10 or 11), which requires placing the file in a specific system folder. How to Fix fast2001.ocx Errors

You should see a success message: "DllRegisterServer in fast2001.ocx succeeded" . Troubleshooting Common Errors

ActiveX controls were notorious for security vulnerabilities. If you found FAST2001.ocx randomly on your computer and you are not trying to run a specific legacy app, it is worth scanning it with VirusTotal before registering it. Many older controls can be hijacked to run malicious code.

Most modern Windows operating systems are 64-bit. However, many fast2001.ocx components are 32-bit. Running a 32-bit OCX on a 64-bit system requires explicit registration in the SysWOW64 folder, not System32 . A common mistake is using the wrong regsvr32 .