Support setting default PDF viewer for opening Deep Links

Currently, PDF tools like PDFpen and Skim support Deep Linking to specific text in a PDF document. On the hand, other PDF tools like PDF Expert may be the preferred tool for reading PDF documents. However, tools like PDF Expert does not support Deep Linking yet. Therefore, is it possible to support setting a default PDF tool for the purpose of Deep Linking? Then the workflow may be as follows:

  • One reads PDF documents in a preferred tool like PDF Expert and annotate and take notes there.
  • If one wants to Deep Link to specific text in the PDF document, one uses another PDF tool like Skim for Deep Linking purpose.
  • After reading, if one wants to navigate to a specific Deep Link, one may click the link, and it would go to the specific text in the set default PDF viewer for Deep Linking, e.g. Skim.

The main reason for not setting a default PDF viewer that supports Deep Linking system-wide is that the reading experience of such a PDF tool may not be desired. For this, it would be great if one can set a default PDF tool for Deep Linking purpose. There can be the following options for this purpose:

  • One can set the system-default PDF tool for opening Deep Links.
  • Instead, one can choose to set a PDF tool that is not system-default for opening Deep Links.
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My skim crashes frequently when I jump to a pdf using deep linking. Don’t know why.

thank you and we agree it would be helpful particularly in this case. I’m sorry we haven’t gotten to it yet.

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Welcome to the Hook Productivity Forum , @ghs2015. could you please let us know your version of Skim , macOS and Hook?
Does this happen with any PDF? Any deep link?
What language is your macOS set to?
can you paste an example deep link?
can you try with a PDF that is in the home folder or Documents folder to see if it makes a difference?

Hook simply calls some AppleScript, so it sounds like Skim is having difficulty with the AppleScript call for some reason.

Thank you very much for the reply.
My Skim version is Version 1.6.5 (135).
OS version: Monterey 12.0 Beta (21A5534d)
Hook version: Version 3.2.1 (4468; Integration v. 182)
This only happens with Skim. And I followed the instructions to setting skim as the default pdf viewer.
OS language is US English.
When I tried pdf under the home directory, it worked as before. The previous location of the same file is at an external drive, which seems to be the reason.

Is there any way to fix this? Thank you!

This may address that issue: Hook 3.3 public BETA 5 – Hook. (not hanging, but URL resolution on the external drive.)

Thanks for the solution. I will move the pdf back to the external drive. :joy:

+1. Any update on this feature? Thank you!

Yes, the problem should be solved. Hook 3.3 was released last month Latest is 3.3.2:
Hook Version 3.3.2 official release is now available - Releases - Hook Productivity Forum.

I think I may be misunderstood. I am referring to this.

it’s not possible to do that, at least at the moment. Hook relies on the OS to choose the app with which to open files.

Hi LucB,

I am struggling to make the deep link of pdf to be working on my mac. Previously, I just try using Skim, but had no luck with it. I thought it was just too complicated with the apple script issues. Actually, I have already tried to use the updated version, which is on 1.6.8. I also try to download your Mental Pertubance pdf, however, the link did not work at all on my mac. So eventually I just try to use the PdfPenPro as well. Still no luck with it. For the link that I get, it was only directed to the pdf file on the finder. It seems there is a bigger issue lies on my mac, even with the PdfPenPro.

Currently, I am on Mac OS Monterey 12.1 (21C52)
Hook Version 3.4.1 (4604; Integration v. 192)
Skim 1.6.8 (138)
PDF Pen Pro 13.1

Could you give me any guidance to solve this matter?
Many thanks for your support on this.


Sorry for the trouble.

Could you please copy a deep link from both Skim and PdfPenPro and post here, with no private info?

Thank you

Thanks for your prompt response,

However, due to limitations for me as a new member on this forum, you could access all the links on this file

Many thanks for your help,


Just want to clarify this:

For the link that I get, it was only directed to the pdf file on the finder.

Do you mean it show the file in Finder? If this is the case, could you please click on Gear button in Hook window, then click on Preferences… menu item to open Preferences window?

In general pane of Preferences window, Linking section, uncheck "Reveal hook://file link targets in Finder(rather than opening them). Then try it again.