Go Komura

Apps That Break on Resume from Sleep — How Windows Power Events Work and How to Build Business Apps That Survive Them (archived 2026-08-30)

You opened the laptop and the business app's connections were dead — the cause is a design that never accounted for sleep. This article covers the WM_POWERBROADCAST notification flow, Modern Standby behaviour, disconnect/reconnect design, sleep suppression, and investigation comm...

Volume Shadow Copy (VSS): The Mechanism and the Practice — Why Backup Software Can Copy Files That Are Still in Use (archived 2026-08-30)

Files that are in use can't normally be copied because of sharing violations — so how does backup software manage it? This article explains the roles of the Volume Shadow Copy Service (VSS) requester, writer, and provider, how copy-on-write works, day-to-day vssadmin operations,...

The Differences Between Windows PowerShell 5.1 and PowerShell 7 — A Practical Guide to Migrating In-House Scripts (archived 2026-08-30)

The relationship between Windows PowerShell 5.1 and PowerShell 7 (side-by-side coexistence and pwsh.exe), Microsoft's official position that 5.1 gets no new features, garbled text caused by encoding differences, defending yourself with #Requires, and updating Task Scheduler — the...

Registration and Bitness Pitfalls in COM/OCX/ActiveX Development (archived 2026-08-30)

Why COM/OCX components fail with 0x80040154 or break outside your dev machine: bitness mismatches, regsvr32 vs Regasm, HKCR views, and admin-rights traps. Archived version of https://comcomponent.com/en/blog/2026/04/15/001-com-ocx-activex-pitfalls-visual-studio-bitness-admin-righ...

A Practical Guide to Windows LAPS — Retiring the Shared Local Administrator Password Across All PCs (archived 2026-08-30)

A shared local administrator password across every PC is fertile ground for Pass-the-Hash attacks, where the compromise of one machine spreads to all of them. This article explains automatic rotation with Windows LAPS — now a built-in OS feature — how to configure storage in Acti...

The Depths of Windows Virtualization (Part 3) — Virtual Machines That Boot in Seconds: Why WSL2, Windows Sandbox, and Containers Are So Light (archived 2026-08-30)

Why do WSL2 and Windows Sandbox start in seconds and feel so light? This article explains the mechanisms, from dynamic base images and direct map through dynamic memory allocation to Hyper-V isolated containers. Archived version of https://comcomponent.com/en/blog/windows-virtual...

What Do the Eight Digits of an Insurer Number Tell You? — Law-Type Numbers, Prefecture Numbers and Check Digits Read from a Receipt Computer's Implementation (archived 2026-08-30)

The insurer number on a Japanese health insurance card is made up of a 2-digit law-type number, a 2-digit prefecture number, a 3-digit per-insurer number and a 1-digit check digit. Taking the Ministry of Health, Labour and Welfare's setting guidelines as the primary source, this...

A Practical Guide to Group Policy (GPO) — How It Works, Confirming Application, and Choosing Between GPO and Intune (archived 2026-08-30)

Are you working in an AD environment without really knowing what "distributed via GPO" means? This article explains, from a practical standpoint, how Group Policy works and the LSDOU order of application, confirming that changes have taken effect with gpupdate and gpresult, choos...

Never Use a QR Code's Decoded Value As-Is — Error Correction Succeeding Does Not Guarantee the Value (archived 2026-08-30)

QR code error correction is not a mechanism that guarantees the value is correct once correction succeeds. Using sample images and measurements from two different decoders, this article explains why a symbol can be read as a different value depending on where the damage lands, an...

Process Explorer / Handle / VMMap in Practice — Chasing Hangs, Leaks, and "File in Use" from the State Right Now (archived 2026-08-30)

Part two of our practical Sysinternals series, covering "it gets slower and slower," "the file can't be deleted," and "it hung." We look at Process Explorer's handle search, thread stacks, and leak-monitoring columns, at handle.exe, and at breaking down a memory footprint with VM...

Registry 32-bit/64-bit Redirection and Virtualization Pitfalls — Wow6432Node and the "The Value I Wrote Isn't There" Problem (archived 2026-08-30)

How a 32-bit app's writes to HKLM\Software get redirected to Wow6432Node, the conditions under which UAC virtualization diverts them to the VirtualStore, the real damage caused when COM registration splits by bitness, and how to read and write correctly using RegistryView and reg...

Hardening PowerShell — Logging, AMSI, Language Modes, and JEA (archived 2026-08-30)

A practical guide to using PowerShell safely instead of banning it. Covers enabling script block logging and transcription, AMSI and disabling the old engine, restricting execution with language modes, and delegating privileges with JEA. Archived version of https://comcomponent.c...

The Depths of Windows Virtualization (Part 1) — Where Is Your Windows Actually Running? The Hypervisor and Partitions (archived 2026-08-30)

When you enable Hyper-V, the host Windows itself runs on top of the hypervisor as the root partition. This article explains the foundations of virtualization through the roles of VT-x, SLAT, and VMBus. Archived version of https://comcomponent.com/en/blog/windows-virtualization-in...

Taking Inventory of a File Server with PowerShell — Capacity Analysis and Access Permission (ACL) Auditing (archived 2026-08-30)

A practical procedure for taking inventory of a file server with PowerShell. Covers capacity analysis and recording access denials, listing old files and extracting duplicate candidates by hash, permission auditing with Get-Acl and detecting broken inheritance, producing CSV repo...

Can You Use a Subsidy to Outsource System Development? — A Map of the Programmes by Purpose, and the Pitfalls to Know Before You Place an Order (FY2026 Edition) (archived 2026-08-30)

Can you use a subsidy to outsource system development? This article explains why "bespoke development on the IT Introduction Subsidy" does not work, maps out the programmes by purpose — including the Monozukuri (Manufacturing) Subsidy — and covers pitfalls such as the ban on plac...

Replacing an Excel Ledger with a SharePoint List — Sharing, History, and Flow Integration to Put an End to the Broken Ledger (archived 2026-08-30)

A practical guide to migrating an Excel ledger on a shared folder to a SharePoint list (Microsoft Lists). Covers solving concurrent editing, overwrites and row misalignment, the import procedure from Excel, column type design, a correct understanding of the 5,000 list view thresh...

Packet Capture on Windows in Practice — Choosing Among pktmon, netsh trace, and Wireshark (archived 2026-08-30)

A communication failure that leaves only "timeout" in the app log can be investigated one layer deeper by looking at the packets that actually went over the wire. Even on servers where you cannot install Wireshark, you can capture with the inbox pktmon and netsh trace. This artic...

How the Clipboard and Drag & Drop Work — Handling OLE Data Transfer Correctly in Business Apps (archived 2026-08-30)

Paste an Excel table and the formatting falls apart; close the source app and you can no longer paste — both come from the clipboard placing the same content in multiple formats at once. This article covers standard formats, delayed rendering, OLE drag and drop, and the policies...

Parameter Design and Modularization for PowerShell Scripts — From a Script That Works to a Script You Can Hand Over (archived 2026-08-30)

A step-by-step procedure for raising a PowerShell script to a quality you can hand to someone else. Covers the param block and [CmdletBinding()], input validation, pipeline input, -WhatIf support, .psm1 modularization, and the essentials of internal distribution and Git managemen...

Distributing and Updating PowerShell Modules In-House — PSResourceGet and an Internal Repository (archived 2026-08-30)

How to move on from copying and reusing ps1 files in a shared folder. Covers how to write a module manifest, versioning, building an internal repository with PSResourceGet and distributing and updating through it, and how it combines with code signing. Archived version of https:/...