"After this date, you will no longer be able to open or edit these files with Microsoft Publisher"...

Microsoft Publisher is being retired for Microsoft 365 subscribers, but this does not equate to Microsoft deleting or seizing customer content.

From the documented plan:

• Publisher reaches end of life in October 2026.
• For Microsoft 365 subscribers:
  • Publisher will no longer be included in Microsoft 365.
  • Publisher will no longer be available for installation or download after October 2026.
  • Publisher files (.pub) will no longer be openable or editable using Microsoft Publisher after that date.
• For perpetual (non‑subscription) versions of Publisher (for example, Office LTSC 2021):
  • Support ends October 1, 2026, when Office LTSC 2021 reaches end of support.
  • The app can still be installed and used beyond that date, and .pub files can still be opened and edited with that perpetual copy.

The key points regarding access to content:

1. Files remain the customer’s data
   • Existing .pub files are not deleted or encrypted by Microsoft.
   • They remain accessible as files on local storage, OneDrive, or SharePoint.
   • The change is that Microsoft 365 subscribers will no longer have the Publisher application available to open them.
2. Microsoft is providing a migration path
   • Before 10/1/2026, customers are explicitly advised to convert .pub files to other formats:
     • To view content after retirement: convert .pub to PDF.
       • Open the Publisher file.
       • File → Save As → choose location → select PDF as file type → Save.
     • To edit content after retirement:
       • Convert .pub to PDF, then open the PDF in Word:
         • Open Word.
         • File → Open → select the PDF.
         • Click OK to convert; Word opens an editable document (layout may differ, especially with many graphics).
     • Alternatively, third‑party tools can be used to convert directly from Publisher to other formats (quality and support vary, and Microsoft does not support those tools).
3. Bulk conversion is supported
   • For large numbers of .pub files, automation is supported via PowerShell to bulk export to PDF.
   • The documented approach:
     • Ensure a working, licensed Publisher installation.
     • Use the sample PowerShell script (Example conversion script) to convert files in bulk.
     • Example usages:
       • Convert-PubFileToPDF.ps1 -Filter "C:\\Documents\\MyFile.pub"
       • Convert-PubFileToPDF.ps1 -Filter "*.pub"
       • Convert-PubFileToPDF.ps1 -Filter "*.pub" -Recurse
       • Convert-PubFileToPDF.ps1 -Filter "C:\\Documents*.pub"
       • Convert-PubFileToPDF.ps1 -Filter "C:\\Documents*.pub" -Recurse
   • The script is designed to continue on errors and report which files succeeded or failed.
4. Alternatives within Microsoft 365
   • Many Publisher scenarios are already supported in other apps:
     • Ads/Flyers, Brochures, Certificates, Business cards, Calendars, Cards: Word or PowerPoint.
     • Banners/Signs/Posters: PowerPoint.
     • Business invoices, applications, forms; Envelopes; Labels; Letterhead; Newsletters; Programs/Folded paper projects: Word.
   • Templates for these scenarios are available via Microsoft 365 apps and Microsoft Create.
5. Practical implication for Microsoft 365 subscribers
   • The subscription includes access to specific apps and services for as long as they are part of the subscription offering.
   • When an app is retired from the subscription, the right to use that app under the subscription ends, but the customer’s files remain and can be:
     • Converted before retirement using Publisher.
     • Opened later using a perpetual Publisher license (if purchased separately and installed on a supported system).
     • Opened/edited via converted formats (PDF/Word) or third‑party tools.

To avoid losing practical access to .pub content under Microsoft 365, the documented recommendation is to convert existing Publisher files to other formats before October 1, 2026, or maintain a perpetual Publisher installation that can still open and edit them after that date.

References:

• Microsoft Publisher will no longer be supported after October 2026
• I have thousands of Publisher files; I'm not opening each one individually to convert them. What is this BS about retiring publisher and losing access to all those files? This is 20 years of work that my business is going to lose, we won't recover from th - Microsoft Q&A