Microsoft Word's Similarity Checker Retires in 2026: Why Every M365 Deprecation Is a Patch Management Problem

On October 3, 2026, Microsoft will retire Word's Similarity Checker — the plagiarism and text-matching tool inside Microsoft Editor. It will simply be gone from the Editor experience. And Microsoft has been explicit about something every admin should clip and save: Microsoft 365 Copilot is not a formal replacement for similarity or originality validation.

If you run a Microsoft 365 tenant — especially in education, legal, publishing, or any content-review-heavy organization — this is more than a feature note. It's another entry on the long list of changes Microsoft delivers silently through the Office update pipeline, on Microsoft's schedule, not yours.

The uncomfortable question for IT teams: if a stakeholder asked today, "Which of our machines and users will be affected when this disappears?" — could you answer in under a minute? If your honest answer involves a stale spreadsheet or a guess, keep reading.

Deprecations Are Update Events — Most IT Teams Don't Treat Them That Way

Microsoft 365 Apps are Click-to-Run. They don't sit still. Every endpoint pulls builds from Microsoft's CDN based on its update channel — Current Channel, Monthly Enterprise Channel, or Semi-Annual Enterprise Channel. Features appear, change, and disappear as builds change.

That means when a deprecation like the Similarity Checker takes effect, your fleet will not be uniform. The marketing laptops riding Current Channel will look different from the finance desktops parked on Semi-Annual. The classroom machines that haven't updated since spring will look different from both.

A feature retirement is, mechanically, an update event. Update events are exactly what patch management is supposed to give you control over — which is why this belongs in your patch process, not in a Message Center post nobody triages until users start complaining.

The Problem in Depth: Where This Breaks in Real Environments

1. The announcement dies in Message Center. The typical enterprise tenant receives dozens of Message Center posts per month. Nobody owns triage. The retirement notice sits unread, and on October 5, 2026 — the first business day after the cutoff — the helpdesk gets its first ticket: "The similarity checker button is gone from Word. Is it broken?"

2. The tech can't tell change from breakage. Without device context, the tech does the classic dance: quick repair of Office, then a reinstall, 25 minutes of troubleshooting — before someone finally finds the deprecation notice and realizes it's by design. Multiply that across a writing-intensive department — legal reviewers, grad students, the content team — and one uncommunicated deprecation generates 40–60 tickets in the first week at 20–30 minutes each. That's a full tech-week burned on something Microsoft announced a year in advance.

3. The tools don't talk. Standalone RMM tools treat Office patching as a binary "is it current?" check. Standalone monitoring doesn't carry software inventory. The helpdesk has no idea what build is on the device in the ticket. So the three systems that could answer the question together — who has what build, did the update apply, what do we tell the user — each hold one-third of the truth, in three different consoles.

4. The patch foundation underneath is shaky. WSUS is deprecated, and teams are mid-migration to Windows Update for Business and Intune — while M365 Apps channel settings are still managed by vibes and Group Policy folklore at plenty of shops. Nobody can quickly say how many endpoints are on Monthly Enterprise versus Semi-Annual, or which devices have a pending reboot blocking the next build.

5. MSPs get it worst. One deprecation × 30 client tenants = 30 rounds of the same scramble, with a technician keeping twelve tabs open across five consoles just to figure out which client is even affected.

The downstream costs are familiar: longer downtime for affected workflows, ballooning ticket volume, SLA misses that only show up in a report three weeks later because the helpdesk and monitoring data live in separate systems, and the slow morale drain of a team that always learns about Microsoft's changes from end users instead of from its own tooling.

How AlertMonitor Closes the Gap

AlertMonitor was built on a simple premise: patching, monitoring, and the helpdesk should share one source of truth about every device. Here's what that changes for a deprecation like this one:

Live patch and build visibility. The patch management module tracks every managed Windows device in real time — including which Microsoft 365 Apps build and update channel each machine runs, which devices are missing updates, which have failed patches, and which are sitting on a pending reboot. "Who's affected?" becomes a 30-second filter, not a week of archaeology.

Staged, scheduled rollouts. Channels and updates get deployed deliberately, by department or device group. Put the writing-heavy teams on Monthly Enterprise so feature changes land predictably; let the billing terminals ride Semi-Annual. Schedule the window, stage it, watch it complete — instead of letting Microsoft's CDN run your change management for you.

Rollback when a build bites. When a new Office build breaks that legal document-management add-in at 9am on a Tuesday, you roll the group back and keep the business running while you investigate — rather than firefighting end-user-driven downgrades.

Monitoring with patch context. Because patch status is integrated with monitoring, a device that reboots unexpectedly at 2am after an update fires an alert with full context — which update, which build, before and after. Not a mystery outage discovered by users at 8am and escalated through four people.

Helpdesk that knows the device. When the "similarity checker is gone" tickets do arrive, the tech opens the ticket and sees the device's Office build, channel, and patch history inline. One knowledge base article, linked to the deprecation event, mass-applied across the ticket wave. Five minutes of triage instead of 25 minutes per ticket of Office repair theater.

One console for MSPs. A multi-tenant NOC view across all clients, with per-client patch compliance you can export as evidence: "100% of Client X endpoints on approved channel and build."

Old way vs. AlertMonitor way, in one line each: the old way, users discover Microsoft's changes first and IT investigates after; the AlertMonitor way, IT schedules the change, monitoring confirms it, and the helpdesk answers before the first ticket lands.

Practical Steps You Can Take This Week

Step 1: Inventory your M365 Apps builds and channels. Run this on a representative endpoint to see exactly what's installed:

# Get Microsoft 365 Apps build and update channel for the local machine
$config = Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration" -ErrorAction SilentlyContinue

$channelMap = @{
    "492350f6-3a01-4f97-b9c0-c7c6ddf67d60" = "Current Channel"
    "64256afe-f5d9-4b86-8952-7e0d3de5c11e" = "Current Channel (Preview)"
    "55336b82-a18d-4dd6-b5f6-9e5095c314a6" = "Monthly Enterprise Channel"
    "7ffbc6bf-bc32-4f92-8982-f9dd17fd3114" = "Semi-Annual Enterprise Channel"
    "b8f9b850-328d-4355-9145-c59439a0c4cf" = "Semi-Annual Enterprise Channel (Preview)"
}

$guid = ($config.CDNBaseUrl -split "/pr/")[-1]

[PSCustomObject]@{
    Computer = $env:COMPUTERNAME
    Build    = $config.VersionToReport
    Platform = $config.Platform
    Channel  = $channelMap[$guid]
} | Format-List

Step 2: Sweep the fleet and export the results. This is the report you want in hand before every future deprecation:

# Export Office build and channel for a list of machines to CSV
$machines = Get-Content "C:\Scripts\m365-endpoints.txt"

$channelMap = @{
    "492350f6-3a01-4f97-b9c0-c7c6ddf67d60" = "Current Channel"
    "64256afe-f5d9-4b86-8952-7e0d3de5c11e" = "Current Channel (Preview)"
    "55336b82-a18d-4dd6-b5f6-9e5095c314a6" = "Monthly Enterprise Channel"
    "7ffbc6bf-bc32-4f92-8982-f9dd17fd3114" = "Semi-Annual Enterprise Channel"
    "b8f9b850-328d-4355-9145-c59439a0c4cf" = "Semi-Annual Enterprise Channel (Preview)"
}

$results = foreach ($machine in $machines) {
    try {
        $cfg = Invoke-Command -ComputerName $machine -ScriptBlock {
            Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Office\ClickToRun\Configuration" -ErrorAction Stop
        }
        $guid = ($cfg.CDNBaseUrl -split "/pr/")[-1]
        [PSCustomObject]@{
            Computer = $machine
            Build    = $cfg.VersionToReport
            Platform = $cfg.Platform
            Channel  = $channelMap[$guid]
            Status   = "OK"
        }
    }
    catch {
        [PSCustomObject]@{
            Computer = $machine
            Build    = ""
            Platform = ""
            Channel  = ""
            Status   = "Unreachable or not Click-to-Run"
        }
    }
}

$results | Sort-Object Channel, Computer |
    Export-Csv -Path "C:\Reports\office-build-inventory.csv" -NoTypeInformation
$results | Format-Table -AutoSize

Step 3: Find pending reboots that will block the next build. Half of "we updated everyone" fleets have machines that never actually finished:

# List machines with a pending reboot that blocks update completion
$machines = Get-Content "C:\Scripts\m365-endpoints.txt"

foreach ($machine in $machines) {
    $pending = Invoke-Command -ComputerName $machine -ScriptBlock {
        @(
            Test-Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired"
            Test-Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\RebootPending"
        ) -contains $true
    }
    if ($pending) {
        [PSCustomObject]@{ Computer = $machine; PendingReboot = $true }
    }
}

Step 4: Choose channels on purpose. Decide per user group which channel they belong on, and write it down. Deprecations will then hit fleets you understand, on schedules you predicted.

Step 5: Build the deprecation triage loop. Message Center post → filter affected devices → schedule the staged change → brief the helpdesk with a KB article → confirm completion through monitoring. In AlertMonitor, this is one workflow: create or update the patch policy, assign it to the device group, pick the maintenance window — and the same platform that deployed it alerts you if anything fails or reboots, while arming the helpdesk with device context when users ask questions anyway.

Step 6: Handle the actual Similarity Checker gap. Microsoft has said plainly that Copilot is not a formal replacement for similarity or originality validation. If your org — or a client — relies on it, evaluate dedicated originality-checking tools now, well before October 2026, and roll that software out through the same staged patch pipeline so you know exactly where the new tool landed and where the old feature disappeared.

The deprecation itself is minor. The pattern isn't: Microsoft ships change continuously, and the only teams that stay ahead of it are the ones that can see, stage, and verify updates on every device from one place.

Related Resources

AlertMonitor Patch Management & Software Updates AlertMonitor Platform Overview Book a Demo Patch Management & Software Updates Resources