Replication problems between domain controllers are often silent for weeks before they cause a visible symptom. A password change that doesn’t propagate, a GPO that applies inconsistently, a user showing up in one site but not another. Checking replication health proactively with repadmin and dcdiag catches these before they become a support ticket. Start with […]

How to Set Up and Test Active Directory Replication Health Andrew Armstrong

Diagnose Windows driver problems properly: read the error code, roll back cleanly, stop Windows Update reinstalling a bad driver, and use Driver Verifier safely.

Driver Problems on Windows: How to Diagnose and Roll Back Safely Andrew Armstrong

Running your own internal Certificate Authority sounds intimidating but is genuinely one of the more approachable AD-integrated roles once you understand the two-tier design Microsoft recommends: an offline root CA that almost never touches the network, and one or more online issuing CAs that actually hand out certificates day to day. A two-tier PKI (offline […]

Configuring Certificate Services (AD CS) on Windows Server: A Beginner’s Guide Andrew Armstrong

A repeatable PowerShell offboarding process: disable, reset, strip groups, move OU and log it — with -WhatIf support so you can prove what it will do.

How to Automate AD User Offboarding with PowerShell Andrew Armstrong

Air cooler or AIO liquid cooler? What each is genuinely better at, why case airflow matters more than either, and how to pick without overspending.

PC Cooling Explained: Air vs AIO and What You Actually Need Andrew Armstrong

Renaming a domain controller is fully supported by Microsoft, but it’s not a simple right-click-rename like a member server. It needs to go through netdom computername so AD, DNS, and Kerberos all stay in sync. Do it the manual way and you’ll end up with orphaned SPNs and broken authentication for anything referencing the old […]

How to Rename a Domain Controller Safely Andrew Armstrong

File Explorer crashing or freezing on Windows 11: how to isolate a bad shell extension, the folder-optimisation bug behind slow folders, and what actually fixes it.

How to Fix File Explorer Crashing or Freezing on Windows 11 Andrew Armstrong

AD FS lets your on-premises Active Directory issue security tokens so users can single sign-on into external services (Office 365 in hybrid setups without Entra Connect sync, SaaS apps supporting SAML/WS-Fed) without those services ever seeing an AD password directly. It has a reputation for being fiddly to set up, and the reputation is earned […]

Active Directory Federation Services (AD FS): Setup and Common Errors Andrew Armstrong

Ready-to-run PowerShell queries for auditing Active Directory: stale accounts, privileged group membership, password policy exceptions and delegation risks.

Auditing Active Directory with PowerShell: Practical Queries Andrew Armstrong

Clean a PC without damaging it: why compressed air needs care, when thermal paste actually needs replacing, and how to check whether it worked.

How to Clean a PC Properly: Dust, Paste and Thermals Andrew Armstrong