SAS® 9.4 returns "Invalid Physical Name for Library SASUSER" after applying 2026 Microsoft Windows Security Updates


Overview

After applying the June 2026 Microsoft Windows Security Updates (released on June 9, 2026) and/or the July 2026 Microsoft Windows Security Updates (released on July 14th, 2026), SAS® 9.4 customers might be unable to start Base SAS® or connect to a SAS server from SAS® Enterprise Guide®.

This issue occurs after installing the following Microsoft Updates:

When the issue occurs, launching Base SAS fails during initialization, and SAS Enterprise Guide is unable to connect to Base SAS.

Symptoms

When you start Base SAS, the following errors appear:

ERROR: Invalid physical name for library SASUSER.
NOTE: Unable to initialize the options subsystem.
ERROR: (SASXKINI): PHASE 3 KERNEL INITIALIZATION FAILED.
ERROR: Unable to initialize the SAS kernel.

Cause

When installed, the June 2026 Microsoft Security Updates released on June 9, 2026, and/or the July 2026 Microsoft Security Updates released on July 14th 2026, have been found to affect the Windows known folder resolution for the ?FOLDERID_Documents folder, but only when the logged on User's Documents folder is redirected to a remote network location.

When SAS attempts to initialize the SASUSER library by using the affected Documents folder path, SAS might be unable to resolve the location correctly. This prevents the SAS options subsystem and SAS kernel from initializing successfully.

Determine the Documents Folder Path

To determine the current Documents folder path for the affected Windows user account, run the following PowerShell command:

(Get-ItemProperty -Path "HKCU:\software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders" -Name Personal).Personal

This command returns only the Personal value from the Windows User Shell Folders registry key. The Personal value identifies the path that Windows is using for the user's Documents folder.

If the Personal value returns a path to a network or other non-local drive, such as a UNC path, that indicates the Windows user account is affected by this problem.

For example, a returned path similar to the following indicates that the Documents folder is redirected to a network location:

\\network.machine.com\Users\userID\Documents

Workaround

SAS is currently working on a fix for this issue. Until a fix is available, you can work around the problem by explicitly setting the -SASUSER option in the SAS configuration file to use the resolved Documents folder path.

Note: Administrator rights on the machine are required to complete the following workaround steps.

Step 1: Back Up the SAS Configuration File

Make a backup copy of the sasv9.cfg file before making changes.

The default English-language configuration file location is:

C:\Program Files\SASHome\SASFoundation\9.4\nls\en\sasv9.cfg

Note: Your SAS installation path or locale-specific nls directory might be different.

Step 2: Identify the Documents Folder Path

Run the following PowerShell command:

(Get-ItemProperty -Path "HKCU:\software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders" -Name Personal).Personal

Copy the returned Documents folder path.

Step 3: Update the -SASUSER Option

Open the sasv9.cfg file in a text editor that has administrator privileges.

Locate the -SASUSER option and update it to use the Documents folder path from Step 2, followed by:

\My SAS Files\9.4

Use the following format:

-SASUSER "<Documents folder path>\My SAS Files\9.4"

For example:

-SASUSER "\\network.machine.com\Users\userID\Documents\My SAS Files\9.4"

Note: If multiple SAS users share the same machine and their Documents folders follow a consistent naming convention that includes their Windows user ID, you can use the %USERNAME% environment variable so that each user automatically receives a unique SASUSER location. 

For example:

-SASUSER "\\network.machine.com\Users\%USERNAME%\Documents\My SAS Files\9.4"

When SAS starts, %USERNAME% is replaced with the currently logged-in Windows username. This allows multiple users to share the same SAS installation while maintaining separate SASUSER directories.

Step 4: Save the Configuration File

Save the updated sasv9.cfg file.

Step 5: Restart SAS

Start Base SAS or reconnect from SAS Enterprise Guide.

The SAS session should now initialize successfully.

Additional troubleshooting: If the Microsoft Windows updates identified above were not installed, or if this workaround does not resolve the problem, see SAS KB0039550, "An 'Invalid physical name for library SASUSER' message is displayed at startup for SAS® 9.4 and earlier releases in a Windows operating environment," for additional troubleshooting steps.

Additional Notes