Adobe Acrobat Reader versions 7, 8 and 9 cannot open attachments containing ZIP files. The reason is a restrictive Adobe policy setting in the Windows registry, due to the fact that ZIP files may contain malware. You can change this setting in the registry.

To do so, follow the steps outlined below. Adobe Acrobat Reader 7.x: Do the following to edit the Windows registry and to change the security settings for handling file attachments in Adobe Acrobat Reader 7:

1) Choose Start > Run.

2) Type “regedit” into the “Open” box and click OK to start the Windows registry editor.

3) Navigate to the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\AcrobatReader\[versionnumber]\FeatureLockdown\cDefaultLaunchAttachmentPerms

4) Double-click the following value: sBuiltInPermList

5) Scroll further down the page, if necessary, to locate the file type extension (.zip). The file type extension displays in the right-hand column of the values list.

6) Change the number directly after the file type extension to 1. .zip:1 For more information, please see: Adobe Acrobat Reader 8.x, 9.x: The steps necessary for modification are similar to those for Adobe Acrobat Reader 7.x. The only thing that is different here is the location of the registry key in step 3: HKEY_LOCAL_MACHINE\software\policies\adobe\acrobatreader\[version]\FeatureLockDown\cDefaultLaunchAttachmentPerms