so you can’t open attachments from PDF files?
Problem: You want to open an attachment from a PDF file using a recent version of the Acrobat Reader, but you get a popup saying that your security settings are against you.
Only Google could solve this problem, managing the mess called Adobe online documentation. Adobe’s web site says you must change the security policy. There’s a long talk about how to fix the installer, but I don’t think you want to go that way.
Solution: First log on as an Administrator, because you need access to a protected registry key. That’s HKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Acrobat Reader\7.0\FeatureLockdown\cDefaultLaunchAttachmentPerms. Its default value looks like this:
version:1|.ade:3|.adp:3|.app:3|.asp:3|.bas:3|.bat:3|
.bz:3|.bz2:3|.cer:3|.chm:3|.class:3|.cmd:3|.com:3|.command:3|
.cpl:3|.crt:3|.csh:3|.exe:3|.fxp:3|.gz:3|.hex:3|.hlp:3|
.hqx:3|.hta:3|.inf:3|.ini:3|.ins:3|.isp:3|.its:3|.job:3|
.js:3|.jse:3|.ksh:3|.lnk:3|.lzh:3|.mad:3|.maf:3|.mag:3|
.mam:3|.maq:3|.mar:3|.mas:3|.mat:3|.mau:3|.mav:3|.maw:3|
.mda:3|.mde:3|.mdt:3|.mdw:3|.mdz:3|.msc:3|.msi:3|.msp:3|
.mst:3|.ocx:3|.ops:3|.pcd:3|.pif:3|.prf:3|.prg:3|.pst:3|
.rar:3|.reg:3|.scf:3|.scr:3|.sct:3|.sea:3|.shb:3|.shs:3|
.sit:3|.tar:3|.tgz:3|.tmp:3|.url:3|.vb:3|.vbe:3|.vbs:3|
.vsmacros:3|.vss:3|.vst:3|.vsw:3|.webloc:3|.ws:3|.wsc:3|
.wsf:3|.wsh:3|.zip:3|.zlo:3|.zoo:3|.pdf:2|.fdf:2
The value will be edited in a hex editor provided by Regedit for REG_BINARY values, but you have to pay attention only to the right half of that editor, where the human readable content is placed.
Look for the offending file extension and fix the digit placed after it and after the colon. It should be 2.
PS. Usual disclaimer. Before modifying registry keys (esp. a REG_BINARY value) backup the original values. Be careful, do not open attachments from untrusted sources.