| Error | Cause | Solution |
|-------|-------|----------|
| "Unable to connect to SQL Server" | SQL instance not running | Open Services.msc → Start MSSQL$ASPENV12 |
| "License server not found" | Firewall blocking port 27000 | Add inbound rule for lmgrd.exe and aspen_slm.exe |
| "Visual Basic Script failed" | Missing C++ Redist | Install vc_redist.x64.exe from installer folder |
| "Windows cannot find .DLL" | Antivirus quarantined file | Restore from quarantine and exclude HYSYS folder |
Click Begin Installation. This will take 20–45 minutes depending on your SSD speed.
What happens in the background:
Do not interrupt – even if a command prompt window appears briefly. That is normal.
Select Complete installation (recommended). If you are low on disk space, choose Custom and deselect languages or documentation. how to install aspen hysys v12
Despite best efforts, things go wrong. Here are the top 5 errors and their solutions.
| Error Message | Likely Cause | Fix |
|---------------|--------------|-----|
| “SQL Server installation failed” | Previous SQL instances conflict or Windows user permissions | Uninstall all SQL Server Express instances via Control Panel. Reboot. Install SQL 2019 Express manually from Microsoft before retrying HYSYS. |
| “Error 1935. An error occurred during the installation of assembly component” | Corrupt .NET Framework or Windows Installer cache | Run sfc /scannow in cmd (Admin). Then run DISM /Online /Cleanup-Image /RestoreHealth. Reboot. |
| “License server is not responding” | Firewall blocking port 25734 | Add inbound rule to Windows Defender Firewall for port 25734 (TCP). |
| “HYSYS crashes immediately on launch” | Missing Visual C++ runtimes | Download and install “VC_redist.x64.exe” from Microsoft (2015-2022 combined). |
| “Aspen Property Package Manager error – no databases” | SQL Server not running | Open Services (services.msc), find SQL Server (SQLEXPRESS), set Startup Type = Automatic, and Start it. | | Error | Cause | Solution | |-------|-------|----------|
Once the progress bar hits 100%, you aren't quite done yet.
HYSYS V12 can co-exist with Aspen Plus V12 on the same machine. Install Aspen Plus first, then HYSYS. They share the same License Manager and SQL instance. Do not interrupt – even if a command