Latest .NET Framework Update Fixes Accessibility Tool Unresponsiveness and GC Contention Lock

Following up on its latest Windows 11 Insider build released last week, Microsoft has just announced the preview to July’s Cumulative update for the .NET Framework. This update comes with a few minor changes to enhance reliability by addressing prior issues and bugs that have plagued the framework.

Garbage Collector Fix

The first major fix comes in the form of a config switch that finally tackles the lock contention occurring in Server GC during 2nd generation Garbage Collectors. This was happening due to a high number of both assemblies and GC heaps running simultaneously, causing the Server GC to choke. Following is the .config file that you can implement to remedy this issue.

<configuration>
  <runtime>
    <GCStaticsNoLock enabled="true"/>
  </runtime>
</configuration>

You can also enable the config switch by setting the environment variable “COMPLUS_GCStaticsNoLock” to a value that’s not zero. Keep in mind that if you do not enable the config switch at all then the contention lock will not be fixed and the GC Server behavior will remain the same as before.

Accessibility Tools Fixes

The next two changes are smaller but still equally important ones that help increase the reliability of the .NET Framework by fixing a prominent issue.

  • Firstly, Accessibility Tools was becoming unresponsive due to a few Windows Form applications that were using ToolStrip controls alongside ToolStripControlHost and were running under UI Automation (UIA) Accessibility Tools. The July 2021 update fixes this.
  • Secondly, the Accessibility Tools was unable to differentiate between identical items in the ComboBox and was, once again, becoming unresponsive, all due to a regression in the ComboBox item accessible object. The latest update also fixes this issue.

Unfortunately, no security fixes were added in this update. Microsoft mentions referring to their Security and Quality Rollup published back in February for further details on upcoming security fixes and when you can expect them.

As always, you can download and install the update via Windows Update, where you’ll automatically receive the updates as soon as they are released. For system administrators and advanced users who prefer manual installation, you can check out Microsoft’s update catalog in their official blogpost, and choose to update accordingly.

Huzaifa Haroon
Born and raised around computers, Huzaifa is an avid gamer and a Windows enthusiast. When he's not solving the mysteries of technology, you can find him writing about operating systems, striving to inform the curious.