Let me walk you through practical, actionable steps to fix the frustrating installation errors you’re dealing with—those download failures and "installer no longer supported" messages are common, but we can work through them:

1. Fetch the Latest Installer Package #

The "this version of the installer is no longer supported" error almost always stems from using an outdated installation file. Microsoft regularly updates installers to patch bugs, refresh security certificates, and align with support changes. Grab the most recent version of the Express or Developer installer from the official source, and choose the "Download Media" option instead of the web installer to avoid real-time download issues.

2. Use the Offline Installer to Bypass Network Hiccups #

Your repeated "required file could not be downloaded" errors point to network interference—firewalls, proxy servers, or unstable connections might be blocking the installer from fetching necessary components. Download the full offline installation media (ISO or standalone executable) directly, then run it locally. This eliminates the need for the installer to pull files mid-setup.

3. Verify System Requirements & Windows Updates #

Double-check that your machine meets SQL Server 2019’s minimum specs:

• For Windows 10, you need version 1809 or later
• Windows Server requires 2019 or newer
• Ensure .NET Framework 4.8 is installed (SQL Server 2019 relies heavily on it)
  Also, install all pending Windows updates—outdated system files often cause unexpected installation failures.

4. Temporarily Disable Security Software #

Third-party antivirus, firewalls, or endpoint protection tools frequently interfere with SQL Server’s installation process. Disable them temporarily before running the installer, and remember to re-enable them once setup is complete.

5. Clean Up Previous Installation Remnants #

Failed prior attempts leave behind leftover files or registry entries that can cause conflicts:

• Open the SQL Server Installation Center, go to the Maintenance tab, and select Uninstall to remove all SQL Server 2019 components.
• Head to Control Panel > Programs and Features and uninstall any remaining Microsoft SQL Server 2019-related entries.
• Manually delete the C:\Program Files\Microsoft SQL Server directory (back it up first if you have existing data) and clean up related registry keys (proceed cautiously—always back up the registry before making changes).

6. Run the Installer as Administrator #

Right-click the installer executable and select "Run as administrator". Lack of elevated privileges can prevent the installer from writing files or making system changes, leading to download or installation failures.

If none of these steps resolve your issues, collect the installation logs (they’re usually stored in %programfiles%\Microsoft SQL Server\150\Setup Bootstrap\Log) and share key details from them—this will help pinpoint exactly where the installation is failing.

内容的提问来源于stack exchange，提问作者Sphingidae