Bug: outlook-startup STA-thread COM-blocking stall (reframed from intelconfig-deserialize-stall)

[drmoisan]

• Work Mode: minor-audit

Problem / Why

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Implementation Intent

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Acceptance Criteria

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Dependencies / Risks

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Verification Steps

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Evidence Checklist

• Baseline
• End-state
• Targeted verification

Source

From: docs/features/potential/2026-06-18-outlook-startup-intelconfig-deserialize-stall.md

[drmoisan]

Reframed diagnosis (2026-06-19)

Increment-1 instrumentation (per-resource DeserializeLoaderAsync timing in ReadConfigurationAsync, committed 2bc71fd5) refutes the IntelConfig-deserialize hypothesis this issue was opened on.

Captured [IntelConfig timing] (Run 2):

ResourceKey	SizeBytes	Duration (ms)
People	678	131.23
StoresWrapper	702	1.21
RecentFolders	560	0.45

Deserialization totals ~133 ms. It is not the root cause.

The dominant cost migrates between runs (variable STA-thread COM/RPC block):

Phase	Run 1 (06-18)	Run 2 (06-19)
IntelConfig	~112 s	0.22 s
Events	12.2 s	~131 s
TOTAL	2:09	2:14

In Run 2 the cost is entirely in AppEvents.Hook() (elapsedMs=113334), which performs only three synchronous COM property accesses. A 113 s block in three COM gets on the STA/UI thread is the direct trigger of the ContextSwitchDeadlock MDA (60 s no-pump threshold).

Corrected diagnosis: a synchronous COM/RPC call on the STA/UI thread during startup, whose latency is dominated by Outlook/Exchange responsiveness rather than TaskMaster computation. The blocking site varies (IntelConfig read in Run 1; Hook() in Run 2).

Next (increment 2): add timing around the individual COM accesses in Hook() and around the currently-unmeasured IntelligenceConfig.GetSerializedConfigurations() read, captured across 2–3 cold starts, before scoping the corrective fix.

Two incidental defects from the same capture were split out:

• Bug: log4net-startup-log-directory-not-created #208 — log4net cannot create its logs\ directory (every log write throws).
• Bug: tesseract-engine-initialization-failure #209 — Tesseract OCR engine fails to initialize per image item.

Full reframed scope and acceptance criteria: docs/features/active/2026-06-18-outlook-startup-intelconfig-deserialize-stall-207/issue.md.