Office Reduced Functionality Mode: Old Mac and iPhone Fixes

Microsoft has now put a concrete date on a problem many home-office users will otherwise discover too late.

Starting July 13, 2026, some Office users on older Apple devices may still be able to open and print files, but will no longer be able to edit, save, or create files in Word, Excel, PowerPoint, Outlook, or OneNote.

Microsoft calls this reduced functionality mode.

Who is affected

Microsoft says this can affect:

• Microsoft 365 users on macOS, iPhone, and iPad
• Office 2021 for Mac users
• Office 2019 for Mac users

The key issue is not only which Office license you have. It is also whether the device can run the newer operating system version Microsoft now requires.

Microsoft’s support page says users should be on:

• macOS 12 Monterey or later
• iOS 17 or later

If your Mac, iPhone, or iPad cannot get there, treat this as likely relevant until you verify your Office and OS support path.

What this means in practice

This is not the same as an app disappearing.

The more likely outcome is a home-office trap:

• files still open
• printing may still work
• the app still looks familiar
• editing or saving suddenly stops

That is exactly the kind of failure mode that hurts invoicing, document review, shared spreadsheets, and last-minute client work because the software looks “mostly fine” until the wrong moment.

The practical checklist to run now

1. Check which Office product you actually have

On a Mac, open any Office app and check About Word, About Excel, or the equivalent menu.

Microsoft says if it shows:

• Microsoft 365, you have the subscription version
• Office 2021, you have the perpetual version
• Office 2019, you have the older perpetual version

That matters because the fallback options are different.

2. Check whether the device can run the required OS

Microsoft’s published path is simple:

• Mac users should confirm the device can run macOS 12 or later
• iPhone and iPad users should confirm the device can run iOS 17 or later

If the device cannot update to those baselines, do not assume a later Office reinstall will rescue it.

3. Decide whether this is a software problem or a hardware problem

If the Apple device can run the required OS, the fix is usually:

1. update the OS
2. update Office
3. reopen the apps

If the device cannot run the required OS, this stops being an app-maintenance task and becomes a device-replacement or workflow-migration decision.

4. Identify the files and workflows that would hurt most

Before July, list the work that depends on these apps:

• accounting spreadsheets
• proposal templates
• Outlook mail setup
• OneDrive files
• shared team documents
• local files that are not already synced elsewhere

This is the part many small or solo work setups skip. The risk is often not the app itself. It is the one document flow nobody mapped.

5. Plan your fallback before the deadline

Microsoft says affected users may still have these paths:

• use Microsoft 365 on the web
• install Office on a different supported device
• upgrade the device

For many home-office users, the right answer is not “pick one forever.” It is “have one fallback ready before July 13.”

The Office 2019 and Office 2021 difference matters

Microsoft’s support note is stricter for Office 2019 for Mac.

It says Office 2019 for Mac reached end of support on October 10, 2023, and cannot simply be updated to the required version to avoid this problem.

That makes Office 2019 users the easiest group to underestimate. If an old Mac plus old perpetual Office is still part of your work setup, that combination is already living on borrowed time.

Office 2021 users have a different issue: even if they solve this July compatibility problem, Microsoft also says Office 2021 reaches end of support on October 13, 2026.

So for some users, the real question is not just “How do I avoid July?” It is “Should I avoid doing two migrations in the same year?”

When to treat this as urgent

Move faster if any of these are true:

• the device is your primary work machine
• you rely on local Office apps every day
• the device is too old to update cleanly
• you use perpetual Office and have done no migration planning
• you need Outlook, Excel, or Word to keep working offline

If the affected device is just a backup tablet, the urgency is lower. If it is the machine you use for payroll, invoices, or client documents, it is not low.

The short decision rule

If your Apple device can run the required OS, update it and then update Office before July.

If it cannot run the required OS, stop thinking of this as a simple app update. Use the remaining time to choose between:

• web apps
• another supported device
• a hardware refresh

The expensive mistake is waiting until reduced functionality mode arrives and then discovering the app still opens your files but no longer lets you work.

Sources and further reading

• Microsoft Support: Update Microsoft 365 or Office on your macOS or iOS device
• Related: Microsoft 365 on Windows 10: Support Dates That Matter and Office 2021 End of Support: Small Office Checklist

Frequently asked questions

What is reduced functionality mode in Office?

Microsoft says affected users may still be able to open and print files, but cannot edit, save, or create files in the Office apps.

Does this affect only Microsoft 365 subscribers?

No. Microsoft's support article says it can also affect Office 2021 for Mac and Office 2019 for Mac users, depending on the device and operating system version.

What if my Mac or iPhone cannot update far enough?

Microsoft points users toward Microsoft 365 on the web, another supported device, or upgrading the device. If the hardware cannot run the required OS, a normal Office app update may not be enough.

Last updated May 21, 2026. See our editorial policy. Re-check Microsoft’s live support wording and any device-eligibility notes because support guidance can change.