OBSERVABILITY Signal 472
Microsoft Defender scanned Rider and ReSharper out-of-process components in full, adding tens of seconds to startup
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JetBrains discovered that Microsoft Defender was scanning their out-of-process architecture in full, adding tens of seconds to Rider and ReSharper startup times on Windows, and worked with Microsoft to resolve the issue.
Engineers building desktop applications on Windows should understand that Microsoft Defender applies different scanning rules based on process location, write-protected paths receive wider trust and minimal scanning, while out-of-process components can face full scans adding 10 to 40 seconds to startup. This finding provides a methodology for measuring Defender's impact using ETW logs and explains why some IDEs appear slow to start.
Written by elseif from the cluster below · every claim links back to a sourceThe three things worth knowing
Microsoft Defender scans out-of-process components in full, adding tens of seconds to startup, while processes in write-protected paths receive minimal scanning.
JetBrains IDEs took roughly 10 to 40 seconds to scan at cold start, while Microsoft IDEs had negligible scan times under 1 second.
JetBrains built a measurement tool using Microsoft Defender ETW logs and worked with Microsoft to address the issue, with OOP mode now enabled by default as of version 2026.2.1.
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