Microsoft Sync Framework Runtime v1.0 SP1 (x64) Download Error – How to Fix It in SharePoint

If you’ve ever tried to install SharePoint Server 2019 or 2016 on Windows Server and hit a wall with the prerequisites installer, then you might have received the below error:

“Microsoft Sync Framework Runtime v1.0 SP1 (x64): download error”

I faced this many times. In this tutorial, I’ll walk you through exactly what causes it, and more importantly, how to fix it — including both the online method and an offline workaround if your server doesn’t have internet access.

Recently, when I was trying to install the SharePoint Server in Windows Server, when I ran the prerequisites, it gave me the below error, which says “ Microsoft Sync Framework Runtime v 1.0 SP1 (*64): download error” as shown in the given figure.

What Is Microsoft Sync Framework and Why Does SharePoint Need It?

Before jumping to the fix, let me quickly explain what this component is.

Microsoft Sync Framework Runtime v1.0 SP1 is one of the required prerequisites for installing SharePoint Server 2019, 2016, and 2013. SharePoint uses it to support the Groove client syncing capability (the old-school document sync before OneDrive took over). Even though the Groove client has been deprecated, the dependency is still there in SharePoint 2019 for backward compatibility.

So when the prerequisites installer tries to download this component automatically and fails — usually due to network restrictions, proxy settings, or Microsoft’s download servers being temporarily unavailable — you get that dreaded download error.

Why Does This Error Happen?

There are a few common reasons why the prerequisites installer throws this error:

• No internet access on the server – Many production Windows Servers are locked down and can’t reach external URLs.
• Proxy or firewall blocking the download – The installer tries to pull files from Microsoft’s servers, and the request gets blocked.
• Microsoft’s download link changed or is temporarily unavailable – This has happened, especially with older components like Sync Framework 1.0.
• .NET Framework 3.5 not installed – On Windows Server 2019, .NET 3.5 is not installed by default. Some prerequisite components depend on it, and its absence can cause cascading errors including the Sync Framework one.
• Running the installer without administrator privileges – This can silently fail on certain prerequisite downloads.

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Method 1: Manually Download and Install the Sync Framework (The Easiest Fix)

This is the most straightforward solution, and it works in most cases.

Step 1: Download the installer

Go to the Microsoft Download Center and download Microsoft Sync Framework 1.0 SP1. The file you want is the SyncSetup_en.amd64.zip (for 64-bit systems). Make sure you’re downloading the x64 version — the x86 version will not work for SharePoint.

Direct download page: https://www.microsoft.com/en-in/download/details.aspx?id=17616

Step 2: Extract and run the setup

Once the zip file is downloaded, extract it. Inside, you’ll find a setup file. Double-click it to launch the installer. You’ll see a welcome screen like this:

• Click Next on the welcome screen
• On the license agreement screen, select I Agree and click Next

• On the confirmation screen, click Next to begin the installation

• Wait for the installation to complete — it usually takes less than a minute

Step 3: Re-run the SharePoint prerequisites installer

Once the Sync Framework is installed, go back and run prerequisiteinstaller.exe again from your SharePoint installation media. This time, the installer should recognize that Sync Framework is already installed and move past it without the error.

That’s it — nine times out of ten, this fixes the problem completely.

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Method 2: Offline Installation Using a Command-Line Switch

If your server doesn’t have internet access (which is common in enterprise environments), you can pre-download the Sync Framework MSI file and point the prerequisite installer to it directly using a command-line argument.

Step 1: Download the MSI file on a machine with internet access

From the same download page (https://www.microsoft.com/en-in/download/details.aspx?id=17616), download the package and extract it. Inside the extracted folder, you’ll find a file called Synchronization.msi.

Step 2: Copy the file to your server

Place the Synchronization.msi file in a folder on your server. For example: D:\SPPrereqs\Synchronization.msi

Step 3: Run the prerequisites installer with the /SYNC switch

Open an elevated Command Prompt (Run as Administrator) and run the following command:

.\prerequisiteinstaller.exe /SYNC:"D:\SPPrereqs\Synchronization.msi"

This tells the prerequisites installer exactly where to find the Sync Framework file, bypassing the need for an internet connection entirely.

Note: You can also combine multiple offline prerequisites in one command. For example, if you have all the files downloaded, a full offline prerequisites command looks something like:

.\prerequisiteinstaller.exe /SYNC:"D:\SPPrereqs\Synchronization.msi" /APPFABRIC:"D:\SPPrereqs\WindowsServerAppFabricSetup_x64.exe" /IDFX11:"D:\SPPrereqs\MicrosoftIdentityExtensions-64.msi"

This approach is especially useful when you’re doing repeated installs in a test lab or deploying SharePoint to multiple servers.

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Method 3: Check If .NET Framework 3.5 Is Installed (Windows Server 2019 Specific)

If you’re installing SharePoint 2016 or 2019 on Windows Server 2019, there’s an extra step that often catches people off guard.

Windows Server 2019 does not install .NET Framework 3.5 by default. Some prerequisite components, including certain parts of the Sync Framework setup, depend on it. If .NET 3.5 is missing, you may see the Sync Framework error even after manually installing the MSI.

Here’s how to add .NET 3.5 using PowerShell (run as Administrator):

Install-WindowsFeature Net-Framework-Core -Source "D:\Sources\SxS"

Replace D:\ with the drive letter of your Windows Server installation media. The SxS folder on the ISO contains the required source files.

After enabling .NET 3.5, re-run the Sync Framework installer and then the SharePoint prerequisites installer.

Method 4: Verify the Installation in the GAC

Sometimes the Sync Framework installs silently but the prerequisites installer doesn’t pick it up. This can happen if a previous failed installation left incomplete entries.

To verify whether the Sync Framework is properly registered, check for this DLL in the Global Assembly Cache (GAC):

C:\Windows\assembly\GAC_MSIL\Microsoft.Synchronization\1.0.0.0__89845dcd8080cc91\Microsoft.Synchronization.dll

If the file exists, the Sync Framework is installed. If the prerequisites installer is still throwing the error after that, try running the prerequisiteinstaller.exe again — sometimes it just needs one more pass after all components are in place.

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Things to Keep in Mind

A few important points worth knowing before you try to install SharePoint on any Windows server.

• Always run prerequisiteinstaller.exe as an Administrator. Right-click and choose “Run as Administrator.” Running it without elevation can silently fail on downloads.
• The Sync Framework 1.0 SP1 officially reached end of support in January 2019, but Microsoft has confirmed it remains fully supported within the SharePoint product lifecycle for SharePoint 2013, 2016, and 2019. Do not try to upgrade to Sync Framework 2.1 — SharePoint is not tested with it.
• SharePoint 2019 is the last version that requires Sync Framework. This dependency exists purely for backward compatibility with the old Groove client, and newer OneDrive sync clients do not rely on it.
• Log file location: If you want to see exactly what the prerequisites installer is doing, check the log files at %TEMP%\prerequisiteinstaller.*.log. This gives you a detailed view of which components succeeded and which failed.

Conclusion

Here’s a summary of what to try if you hit the Microsoft Sync Framework Runtime v1.0 SP1 (x64) download error:

1. Manually download and install the Sync Framework from the Microsoft Download Center and re-run the prerequisites installer.
2. Use the offline /SYNC switch if your server has no internet access.
3. Install .NET Framework 3.5 if you’re on Windows Server 2019.
4. Verify the GAC to confirm the Sync Framework DLL is registered properly.
5. Always run as Administrator — it matters more than you’d think.

Once the Sync Framework is properly installed, your prerequisites installer will sail right past that error and continue with the rest of the components.

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