Remote Desktop Services and Accredo

Accredo can be run successfully in environments that use Microsoft Remote Desktop Services (RDS). To achieve good performance and to ensure the safety of your data, it is important that the software is installed in the right way, and that a small number of Windows features are adjusted. This page explains the recommended approach.

Where to install Accredo

For best performance, install both the Accredo Server and the Accredo Client on the same computer that is acting as the Remote Desktop Session Host (RDSH).

This arrangement ensures that:

• All users who connect by Remote Desktop access the Accredo data files locally on that server, rather than across the network.
• Windows’ network file-sharing layer (SMB) is not involved, avoiding delays from network caching and eliminating the risk of silent data corruption.
• Updates to the Accredo Server and Client are applied together. Users receive the new version automatically the next time they restart Accredo. If you use Accredo’s “User Access Times” feature to log everyone out overnight, any update you install will be ready for them the next morning.

Keeping both the Server and Client on the same Remote Desktop Session Host provides the best combination of reliability, performance, and ease of maintenance.

Supported versions of Windows

We recommend running Accredo on the latest currently supported version of Microsoft Windows Server, with hardware suitable for the number of users and other applications being hosted.

For Microsoft’s own information about Remote Desktop Services, see Remote Desktop Services overview.

Note: Remote Desktop Services was previously called “Terminal Services” in earlier versions of Windows Server.

Data access in Remote Desktop environments

Important: Silent data corruption will occur if Accredo data is accessed over SMB in certain Remote Desktop configurations. This corruption is especially serious because it may not be immediately detectable when it happens.

Accredo works well when accessed over a network share from individual Windows desktop or laptop computers. In those situations, Windows’ normal file caching is generally safe.

The situation is different when multiple Remote Desktop Session Hosts are used. If the data is stored on one server and then accessed by several different Remote Desktop Session Hosts, each host will cache information about the files. This behaviour is called opportunistic locking or leasing. While useful for ordinary office documents, it is unsafe for database files that are frequently updated by many users.

To address this, Accredo includes a defeat mode. When enabled, this mode tells Windows not to use these caching techniques for Accredo data. Every change is written directly to the data files, keeping them accurate and consistent. The trade-off is that performance will be slower, because Windows can no longer rely on cached copies.

For this reason, we strongly recommend keeping the Accredo Server and its data on the same Remote Desktop Session Host that users connect to. This avoids network file-sharing altogether and provides the best speed and safety.

For more detail on Microsoft’s guidance about file-server performance and caching, see Performance tuning for SMB file servers.

Drive letters and local access

When the Accredo data is stored on the same Remote Desktop Session Host, always access it using a local path (for example E:\AccredoData).

Do not use a mapped drive letter or UNC path (for example \\Server\E$\AccredoData mapped as E:). Even on the same machine, Windows routes mapped drives through its network redirector, adding unnecessary overhead and re-introducing SMB caching behaviour.

Important: Mapped drives and UNC paths are not supported in Remote Desktop deployments. Even on the same host, they reduce performance, and if any other machine or session connects through the share, silent data corruption will occur.

If you require a drive letter, you can use the SUBST command to create one that points to the local folder. This bypasses the network layer completely.

Fair Share technologies

Microsoft introduced a feature called Fair Share in Windows Server 2012. This technology divides resources (CPU, disk, and network) evenly across Remote Desktop sessions.

• In Windows Server 2012, 2016, and 2019, CPU, disk, and network Fair Share are enabled by default.
• In Windows Server 2022 and later, only CPU Fair Share remains enabled by default. Disk and network Fair Share are disabled by default, but can be turned on manually.

For applications like Accredo that depend on high disk throughput, Fair Share can severely affect performance if disk or network Fair Share are enabled.

Recommendation: Always disable Disk Fair Share if it is enabled. Network Fair Share only applies if Accredo is accessed over a network share. Note that network shares are not supported for Accredo in Remote Desktop deployments. CPU Fair Share can generally be left enabled, as it does not affect file I/O.

To disable Fair Share, your IT provider will need to adjust the following Windows Registry settings:

• Disk Fair Sharing
  Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TSFairShare\Disk
  Value: EnableFairShare → set from 1 to 0
• Network Fair Sharing
  Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TSFairShare\NetFS
  Value: EnableFairShare → set from 1 to 0

More information about this feature is available from Microsoft here: Fair Share technologies enabled by default in Remote Desktop Services.

General Windows Configuration

• Keep Windows Server patched with all current updates.
• Follow Microsoft’s Performance tuning for SMB file servers.
• Disable Offline Files (Client Side Caching) on all Remote Desktop Session Hosts and any client PCs that may access the data.
• Where SMB access cannot be avoided, consider setting the SMB client cache lifetimes to 0 on RDSH machines:
  DirectoryCacheLifetime

FileInfoCacheLifetime

FileNotFoundCacheLifetime

(Located under HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters)

Summary

• Install both the Accredo Server and Client on the same Remote Desktop Session Host.
• Access data through local paths, not mapped network drives.
• Use the latest supported version of Windows Server with appropriate hardware.
• Disable Disk Fair Share (and check Network Fair Share if older servers are used).
• If multiple Remote Desktop Session Hosts must access the same data, enable Accredo’s defeat mode to disable caching, with the understanding that performance will be slower.

Silent data corruption is guaranteed in unsupported configurations such as multiple RDSHs connecting to the same data over SMB.

Mapped drives and UNC paths are not supported in Remote Desktop deployments. Even on the same host, they add overhead and caching behaviour, and if any other machine connects through the share, silent data corruption will occur.

Following the supported design ensures your data remains safe and Accredo runs reliably.