Microsoft’s Latest Updates and Acknowledged Issues
Last week, Microsoft rolled out its latest Patch Tuesday updates for Windows 11, specifically KB5094126 and KB5093998. These updates were accompanied by a series of dynamic updates, including KB5094149, KB5095971, and KB5094156. However, the company has recognized two notable issues that have emerged post-release: malfunctioning Office applications and complications with the Recycle Bin. It is worth noting that additional issues may also be at play.
In a related development, Microsoft has finally addressed a long-standing problem that has persisted for nearly a year. Back in July 2025, the company made a significant change to the default settings of Windows 11, opting for JScript9Legacy in versions 24H2 and later. This shift continued with the release of version 25H2 in October 2025, leading to ongoing compatibility challenges.
The motivation behind the switch to JScript9Legacy was to enhance the security of modern Windows PCs by mitigating vulnerabilities associated with legacy scripting, particularly cross-site scripting (XSS). XSS exploits can allow cybercriminals to embed malicious code into legitimate websites, which can then execute when unsuspecting users visit those sites. The new JScript9Legacy engine was designed to enforce stricter execution policies and improve object handling, thereby reducing the risk of such attacks.
Recently, Microsoft published a support article detailing the compatibility issue, which was highlighted by Neowin during their review. The article explains that JScript global definitions and execution context may not persist across scripts, potentially disrupting older applications and web components that depend on this legacy functionality.
Microsoft has confirmed that this issue arises from its transition away from the older jscript9.dll engine to the newer jscript9legacy.dll. While the latter was intended to bolster security, it also altered how JScript manages execution context. Consequently, functions and definitions established by one script are no longer accessible to subsequent scripts once execution concludes.
Applications that functioned correctly on earlier versions of Windows did so because the older JScript engine maintained global definitions and execution state between scripts. Under the new model, however, this behavior is disabled by default, leading to failures in certain legacy workloads and polyfill-dependent scripts.
To address the issue, Microsoft has released the KB5077241 update. However, this fix is not enabled automatically in subsequent updates. Administrators are required to manually activate persistent JScript execution context through a Registry setting provided by the company. This configuration can be applied to individual processes or system-wide via the FEATUREENABLEPERSISTENCE registry key.
The steps to implement this solution are as follows:
- Run the following command to create the feature control registry key: reg add “HKLMSoftwarePoliciesMicrosoftInternet ExplorerMainFeatureControlFEATUREENABLEPERSISTENCE”
- Under this key, create a new DWORD (32-bit) value.
- Configure the value as follows:
To enable persistence for specific processes only:
Set the value to 1 for each target process name.
To enable persistence for all processes:
Add * as the key name and set its value to 1.
For further details, the official support article is available on Microsoft’s website.
