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How to unblock zip attachments in Adobe PDF files January 7, 2011

Posted by alexoldman in Computer, Security.

There is a neat feature in Adobe PDF’s that supports file attachments. As any security conscious user will know, file attachments can be dangerous, as they may contain malicious executable content.

Adobe have applied a security template to their software, to protect against interaction with various file types. The most frustrating block I frequently come across is a ZIP file. In my opinion as a user I should be able to choose if its safe to open a Zip file that has been embedded in a PDF.

Here is how to remove the policy block on Zip file attachments in Adobe PDF. These instructions work for Adobe Reader or Adobe Standard:

  1. Open Regedit.exe
  2. Browse to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Adobe\<product>\<version>\FeatureLockDown\cDefaultLaunchAttachmentPermsReplacing <product> and <version> as appropriate e.g. HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Adobe\Adobe Acrobat\8.0\FeatureLockDown\cDefaultLaunchAttachmentPerms
  3. Locate in the value list, .ZIP:3 and edit to read .ZIP:1 this changes the behaviour to prompt the user for an action (save or open).
  4. Close Regedit and open Adobe.

You should now be able to open Zip attachments in PDF files.

If this is a corporate problem, you can deploy the Registry update easily using a .REG file, or great a Group Policy to apply using Microsoft Active Directory.



1. Timothy O'Brien - May 3, 2011

Thanks for the post alex, really helped with one of my cases!

Timothy – Sophos support (UK)

Alex Oldman - May 3, 2011

Hi Timothy,

Really pleased to be of help. Your comment has motivated me to blog more frequently.

2. Juergen - May 9, 2011

Just the right Info to save my day! I have a lot of PDFs with zip-Attachments and this saved me a lot of time, work and worries 🙂

3. alexoldman - May 11, 2011

@Juergen – glad to be of help

4. invalidbeard - March 5, 2013

Huge help. Thank you.

5. Terry - March 11, 2013

Someone sent me a zip file..when I receive it it comes as a pdf. What do I do?

alexoldman - April 21, 2013

Sounds like your sender is doing something strange. Try renaming the file to .zip and then opening it.

6. gregorioalvin - April 4, 2013

Thank you! Your tutorial really helped. It worked 🙂

alexoldman - April 21, 2013

Great stuff.

7. Mike G. - May 15, 2013

Very helpful, thanks!

8. Denis - June 11, 2013

How to do that in MAC?

alexoldman - June 15, 2013

Sorry, I don’t know about Mac’s

9. free-minecraftdownload.blogspot.com - January 1, 2014

Aw, this was an incredibly good post. Spending some
time and actual effort to generate a great article… but
what can I say… I hesitate a whole lot and don’t seem to get anything done.

10. Antoine - January 15, 2014

Hello wondering if there is such thing for the zip files in a word document ? I have done some research, but all the info I found refers to outlook. I do not use outlook, just word. Thanks in advance

11. Shimada - January 18, 2014

Thanks for sharing this Alex and to Antoine

12. Cheneen Clark Marks - February 2, 2014

Thank you SO much!!!

13. Carter Massey - May 9, 2014


14. Kevin Keay - July 25, 2014

Many thanks for the post, Alex. I recently purchased some software to extract messages and attachments from old Outlook PST files which doesn’t require Outlook. (I upgraded from Windows XP to 8.1 and no longer have Outlook). There is a free version of this at: http://www.freeviewer.org/pst/ but you need to purchase the full version (Pro) to actually save your messages as PDF files with the attachments embedded. The free version is fine for simply viewing messages and some types of attachments e.g. PowerPoint files, but unfortunately not zip files. I had just tried a set of messages with common attachments and they could all be saved via the attachment option in Acrobat Reader – except for zip files! I tried your fix and it works beautifully!

15. adobe zip file - January 27, 2015

[…] Posted by alexoldman in Computer, Security. trackback. There is a neat feature in Adobe … Download How to unblock zip attachments in Adobe PDF files | Alex … | […]

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