When you open templates or files using a hyperlink button or from Outlook's Shortcut navigation pane, you'll receive an unsafe hyperlink warning. You can disable the warning by editing the registry. You may also receive the file open or save dialog when using a hyperlink button or shortcut. To disable this dialog when the 'Always ask' field is grayed out, run Outlook as administrator. The 'always ask' checkbox should be clickable. If not, you'll need to edit the registry for each file type. See for more information.

The solution The solution applies to all Office applications, not just Outlook. Add a registry value to disable the warning dialog.

HKEY_CURRENT_USER Software Microsoft Office 12.0 Common Security DWORD: DisableHyperlinkWarning Value: 1 (disable the warning), 0 (enable the warning) Note: If the Security key does not exist in your registry, you'll need to create it too. Right click on Security key and choose New, DWORD. Type (or paste) DisableHyperlinkWarning as the Value name then double click on it. Enter 1 as the Value data to disable the warning. Delete the key or use a value of 0 to enable the warning.

Start to add links to PDF on Mac. Now go to the PDF content, and open the 'Edit' panel first then click on the 'Link' button. Select the texts you want to add hyperlink to. Then you will get a pop-up window to input the link. Input the link and click 'OK' and you have created your hyperlink in PDF on Mac (macOS 10.14 Mojave included).

Do It For Me If you don't want to edit the registry yourself, you can download and run the following registry key for your version of Outlook. These files set the key in the User path. Group Policies Registry Edit Administrators will add the DisableHyperlinkWarning DWORD to the Policies key instead.

I found this page the usual (painful) way, having got really cross about MS' attempts to stop me opening valid pdf files (from Excel hyperlinks). I know I have set the DisableHyperLinksWarning value in the past, but today it would not work. This is Office 2010 on W10. I tried all the Trust Centre settings, allowing everything I could find to run, to no avail. Then I saw a suggestion on another page by FrankFromGermany (2 years ago!), but with no mention of whether it had worked for anyone who read it - I was so desperate I had to try it. I first ran Sysinternals' 'ProcMon' to confirm that Excel was trying to open a key in HKEY_CLASSES_ROOTSumatraPDF (my pdf reader of choice) called EditFlags key (and failing, of course), but (as I had closed the page with Frank's suggestion), had to simply try values close to my recollection until one worked - the magic value is Hex 10000. I have turned off all the Trust Centre settings I can think of (including the added trusted folder where the pdfs reside), and it still works.