Here are 2 methods by which you can fix the sage 50 file system error 3112.

Method 1: Disable the Windows Security Firewall

• Open the Start Menu
• In the search box, type the name of the firewall installed in your system
• Click on the Windows Defender Firewall
• Now click on Inbound Rules
• Navigate to the right panel and click on New Rule
• Configure the settings to allow the connection
• Write the name & description of the new rule
• Click on Save to proceed
• Carry out the above steps to create Outbound Rules as well

Method 2: Use the Windows Repair Tool

• Download the Windows Repair Tool
• Save it in a suitable location in your system
• Navigate to the file path
• Double-click to open it
• The UAC window will pop up on your screen. Click Yes to start the installation
• After you launch the tool, a welcome screen will open up
• You will see a check box named “ allow repair tool to start and do scan automatically. Uncheck it
• Now click the Install button to proceed. Make sure your internet connection is not interrupted
• After successful installation, the system will start a scan to check for issues
• After the scan gets completed, the system will specify the errors and show you the areas they belong to
• Now click the Start Repair tab to repair the issues

If the issue still persists, you may have a few ports blocked by the router.  Please speak to your internet service provider to configure the router settings. You can get more details about Sage 50 Errors here .