Can not print mixed size documents using version 26.001.21771

Same happened to company with Canon printers using mixed print size PDFs after recent the update ending 21771.  Was able to get around it by unchecking  "Enable Protected Mode at Startup" and "Enable Enhance Security" in Security (enhanced) options as others have. 

Since the 26.001.21771 reader update, I cannot print my notary documents.  I have lost a considerable amount of money since last week because of this issue.  Adobe does not give you the ability to access earlier versions of the reader.   I have been advised that if this continues to take Adobe to small claims court for the money I have lost and continue to lose.  I have had to turn away another 5 jobs this week.  This is our income and is unacceptable.

This issue needs to be addressed by Adobe immediately! This is affecting the day-to-day operations of my end users. We have a work around for now, but it NEEDS to be fixed! 

This looks like it may be related to Acrobat’s updated print handling after the version change. Try opening Print → Advanced and enable Print as Image as a test. Also check that Choose paper source by PDF page size is disabled and that both Letter and Legal sizes are available in printer settings.

If it works after this, the issue is likely related to page-size processing rather than the printer itself. Hope that helps.

Hi @Amal Jaiswal,

Thank you for your reply.

Here are the results of my investigations:

Environment

• Adobe Acrobat Reader 64-bit 26.001.21771
• Windows 11 25H2
• Multiple workstations affected
• Canon printers (Canon Generic Plus PCL6 driver)
• Microsoft Print to PDF also tested

Troubleshooting already performed

• Cleared Acrobat Reader cache.
• Fully uninstalled and reinstalled Acrobat Reader.
• Tested on multiple Windows 11 workstations.
• Tested with different printers.
• Tested with Microsoft Print to PDF.
• Tested with Foxit Reader using the same PDF files.
• Reviewed PDF properties:
  • PDF Version 1.6
  • Generated with iText Core 7.2.6
  • Documents contain mixed page sizes.

Results

❌ Printing fails when "Choose paper source by PDF page size" is enabled.

✅ Printing works when "Choose paper source by PDF page size" is disabled.

✅ The same documents print correctly with Foxit Reader.

❌ The issue also occurs when printing to Microsoft Print to PDF, which seems to rule out a printer driver issue.

Windows update testing

I initially suspected a recent Windows update because the issue appeared shortly after Windows updates were installed.

To verify this, I:

• Uninstalled KB5101684 (preview update).
• Tested again.
• Uninstalled KB5101650 (security update).
• Tested again.

The mixed-size printing issue remained unchanged.

Therefore, I no longer believe this issue is directly caused by Windows updates.

"Print as Image" testing

I tested the workaround you suggested:

Print > Advanced > Print as Image

Unfortunately, the document still fails to print, even when printing to Microsoft Print to PDF.

This workaround does not resolve the issue in my environment.

About the rollback test

Unfortunately, I am using the free version of Adobe Acrobat Reader and do not have access to previous installers through Adobe support channels.

As a result, I am currently unable to roll back to version 26.001.21677, so I cannot confirm whether the issue was introduced specifically between versions 26.001.21677 and 26.001.21771.

Conclusion

At this point, the evidence suggests a regression related to 26.001.21771:

• Multiple workstations affected.
• Same behavior across systems.
• Reinstallation does not help.
• Microsoft Print to PDF fails.
• Foxit Reader works correctly.
• Disabling "Choose paper source by PDF page size" works around the issue.

Please let me know if Adobe has already identified this issue internally or if there are any logs or diagnostic tools I can provide to help investigate.

Thank you.

This worked for me. 

Disable Protected Mode

Go to Menu > Preferences or press Ctrl + K.Select Security (Enhanced) from the left sidebar.Uncheck the box labeled "Enable Protected Mode at startup" and click OK.Close Adobe Acrobat completely.Open Task Manager and end all Adobe related tasks to make sure everything is fully stopped.Reopen Adobe Acrobat for the changes to take effect.

Since the issue started right after updating to 26.001.21771 and it happens with multiple printers, it sounds more like an Adobe Reader issue than a printer problem.

You should try printing the same PDF with an older version of Reader, if possible, to confirm. You can also try Print as Image (under Advanced in the print dialog) to see if that works. If it does, it may be a bug introduced in the latest update, and Adobe may need to address it in a future patch.

We're experiencing the same issue with the latest 64-bit version of Adobe Reader (26.001.21771). We were able to temporarily resolve the problem by switching to the 32-bit version of Adobe Reader and disabling the following security settings:

• Enable Protected Mode at startup
• Enable Enhanced Security

After completely closing and relaunching Adobe Reader, the options worked as expected.

P.S. I don't remember whether we also ended up using the "Print Ad Image" option.

- Jorge Raigoza
The Computer Support People