Preview Cant Open Multiple PDF in same Window

You can open multiple PDFs in the same window, but the UI is different. Multiple PDFs will now open in separate tabs rather than the old way of segmenting them by scrolling.

Here is a link to the Apple support site if the following steps are not clear:

To ensure all documents open in tabs follow these steps:

Big Sur

(Open) System Preferences > (Select) General > (Go down to 5th option) Prefer tabs: > (Select from option menu^) Always

Older versions of macOS

(Open) System Preferences > (Select) Dock > (Go down to 5th option) Prefer open tabs when opening documents: > (Select from option menu^) Always

Now, when you open multiple PDFs they will open within the same window, segmented by different tabs.

^From the option menu, you have the following options:

Always: When you open another window in your app, it automatically opens as a tab in your current window.

In Full Screen Only: When you open another window in your app, it opens as a tab only if you're using the app in full screen. Otherwise, it opens as a new window.

Manually: Manually choose when to use tabs, whether or not you're using the app in full screen.

If you have multiple PDF files that you want to open in ONE window as ONE file that you can scroll down you can do this:

  1. Open ONLY ONE pdf file in previev.

  2. Use Alt+Cmd+2 (it will open miniatures on the left side).

  3. Select all OTHER pdf files and drag them manually into miniatures sidebar.

Now you have old view in which you can move pages up or down, delete them, add other files, save all as one pdf etc.

High Sierra added tabs in Preview 10.0, so no more multiple PDFs in a single window.

The only known solution to me is to continue using Preview 9.0.

I've taken this from the Github repo I specifically created for this reason, as to retain and make accessible a version of Preview 9.0:

How to get the old behaviour back:

  • Copy with version 9.0 from a computer still running macOS Sierra, or from a Time Machine backup (or download from said repo above)
  • Move to your User/Applications folder (not the one in the sidebar, but in your Home folder - create it if necessary)
  • Set (9.0) as default PDF Viewer for all PDFs (Instructions)

Of course, if you need Preview 9.0 for all users, rename it to and move it to the root Applications folder in the sidebar.

Alternatively, just download Preview 9.0 from your old source, put it on your desktop, and when you want to open multiple pdfs in one page, drag and drop them onto the app icon. You can also create a new file containing all the pdfs in the page by using "Export as PDF".

Not exactly a solution to the problem, but fwiw the work-around I am using is to open a document, show thumbnails, then drag other documents into the thumbnail area in the window. (From the last suggestion here:

From reading around I gather this is a change for the Preview prefs in High Sierra (or earlier) and the "multiple" options are not accessible through the Preview UI in this release.

OP here, I found a more technical work around to this. I'm going to assume the user already knows a bit of how to extract files from packages and use the Terminal.

If you don't : @frhd's answer is probably easier than trying to learn the basics.

Here it goes:

There is a py file included in mac OS that joins PDF files:

/System/Library/Automator/Combine\ PDF\ Pages.action/Contents/Resources/

Extract the python file, so its more convenient:

"cd" to the directory of ONLY THE PDF files you want to combine.

run the python file as so:

./ -o OUTPUT.pdf *pdf

And let it finish, then you will see an OUTPUT.pdf containing all the input PDFs, in the same directory.

**Note, the ordering you get is probably going to be the same as the "ls" ordering, so if you care about order, you have to either modify, or rename the input files.

Anyways, the OUTPUT.pdf is essentially multiple pdfs in one.

You can combine pdf pages into one preview document by:

  1. Open one of the docs.
  2. View the thumbnail sidebar.
  3. Select where you wish to add additional pdf file. (in the thumbnail sidebar)
  4. Select "Edit" from menu then "Insert" and "Page from File"
  5. Click on the file you wish to add.
  6. Save the resulting pdf file that you have added pages to.

Hope this helps.

Another approach is to concatenate the files by dragging and dropping to PDF Toolkit + app.

There are of course other tools on the market like PDFSam and such...