Dependency on OpenSSL 1.1.1
Altair EmployeeAltair SLC makes use of OpenSSL to secure certain communications. OpenSSL is a security utility for working with TLS (SSL) certificates.
Altair SLC 2023, 2024, 2025 requires OpenSSL 3.0 and does not require OpenSSL 1.1.1.
Altair SLC 4.x requires any version of OpenSSL 1.1.1 - the current version is 1.1.1q. OpenSSL is jumping to version 3.0 following relicensing under the Apache license agreement but please note that SLC 4.x versions are dependent specifically on OpenSSL version 1.1.1 and does not work with OpenSSL 3.0.
Shining Light Productions have packaged OpenSSL in a Windows MSI installer package which is convenient to download and install from https://slproweb.com/products/Win32OpenSSL.html.
Please download the Win64 OpenSSL v1.1.1q MSI (not the "Light" version). It is only 63MB and should be quick to download. The downloaded filename is Win64OpenSSL-1_1_1q.msi.
Double-click on the downloaded filename to begin installing OpenSSL. Note that Admin privileges will be required.
If your Windows system alerts you with "Microsoft Defender SmartScreen prevented an unrecognised app from starting." then you're going to have to click on "More info" and then "Run Anyway".
The installer puts the OpenSSL software into C:\Program Files\OpenSSL-Win64.
The installer offers to copy the OpenSSL DDLs (shared libraries) to "The Windows system directory" or "The OpenSSL binaries /bin directory". The former is the default and preferred.
Free free to make a donation to the open source developers of OpenSSL when prompted.