Fix libcrypto.dll (or libssl.dll) errors on Windows

Most common causes

• Architecture mismatch — mixing 32-bit DLLs with a 64-bit app (or vice versa).
• Missing Microsoft Visual C++ Redistributable — OpenSSL depends on the MSVC runtime.
• OpenSSL bin folder not on PATH — Windows cannot find the DLLs at runtime.
• Terminal not restarted after PATH change — old sessions do not pick up new PATH entries.
• App cannot locate DLLs — application looks in its own directory and the DLLs are not there.

Run these in a new terminal first

Fix it in order

• 1

  Match architectures

  On 64-bit Windows use the Win64 installer (Win64OpenSSL_Light-4_0_0.exe). Never mix 32-bit and 64-bit components — this is the single most common cause. Uninstall any 32-bit OpenSSL build and reinstall the 64-bit version from Win64 Prebuilt.

• 2

  Install Microsoft Visual C++ Redistributable (x64)

  Download and install the latest x64 package from Microsoft, then reboot if prompted:

  PowerShell — admin

  PS> Invoke-WebRequest -Uri "https://aka.ms/vs/17/release/vc_redist.x64.exe" -OutFile vc_redist.x64.exe

  PS> .\vc_redist.x64.exe /quiet /norestart

  Or download manually from Microsoft's VC++ page.

• 3

  Add bin folder to PATH

  If where openssl returns nothing, the bin folder is not on PATH. Follow the Add to PATH guide. Default path: C:\Program Files\OpenSSL-Win64in.

• 4

  Restart terminal

  Close all open Command Prompt and PowerShell windows. Open a new one and test again. PATH changes only apply to new sessions.

• 5

  Local DLL deployment (for app developers)

  If you ship an app that uses OpenSSL, copy the DLLs next to your executable. Windows searches the app directory first:

  cmd.exe

  C:\> copy "C:\Program Files\OpenSSL-Win64\bin\libcrypto-3-x64.dll" "C:\MyApp\"

  C:\> copy "C:\Program Files\OpenSSL-Win64\bin\libssl-3-x64.dll" "C:\MyApp\"

Common questions