Dec 03


With Mountain Lion (OSX 10.8) Apple have made it even simpler to join two pdf files together – you just need to drag any pdf file into the thumbnail window of an existing pdf file and the two will be merged together!

Note: this is different for different versions of OS X.

For older versions of OS X (10.6-10.7) click here.

For OS X 10.9 Mavericks click here.


This is a simple 4 click process… (1) Open the first pdf file, (2) Open the thumbnails draw (3) Drag in the second pdf file and (4) Save the new pdf. Here are some pictures to help you do it!

Step 1 – Double click the first pdf file to open it.


Step 2 – Switch to thumbnail view. You can also do this from the top menubar – in the View menu click Thumbnail.


Step 3 – Drag the second pdf file anywhere into the thumbnail window. This copies the whole pdf file in.


Step 4 – Save. It will overwrite the original pdf.


  • Some people are reporting this is not working. (See the comments below). I have no idea why except that maybe you have a different version of the Preview app. Try the instructions in this post even though you don’t have Leopard and it will work!
  • To make a new pdf preserving the original one use ‘Duplicate’ then ‘Save’.
  • To copy only one page, open the second pdf page in thumbnail view and drag just one page across.
  • This does not work with protected pdf files. (Protected pdf files are not common.) If a pdf file has been locked by the author you cannot change it without a password.
  •  It’s a little more complicated on older versions of OSX (eg Leopard, Snow Leopard and Lion) because the exact location that you drop the new pdf makes a difference – see this post for how to merge pdf files in Leopard, Snow Leopard or Lion (10.5,10.6 and  10.7)

72 Responses to “Merge 2 pdf files in Mountain Lion”

  1. William Sievers says:

    Should have read the comment above mine. Overlapping works. Now we still need “Save As” again. Why on earth would they eliminate this easy, one step process and substitute 2 less easy steps? Macs used to be so intuitive. I think the company has been infiltrated by Microsoft operatives.

  2. bernie says:

    thanks heaps . That works well .

  3. Tracie says:

    great works perfect, saved me time and money from not having to download ‘free’ trials for pdf merge software….

  4. danR says:

    Yes, the simple drag-and-drop does NOT work, at least later ML iterations. You must drag and OVERLAP the last thumbnail in the target thumbnail-column before releasing the button.

    Or else you can go to Print and then save it there as a PDF. I’ve tried both ways, both work.

    Apple gets the dunce-cap for this rigamarole; ‘Help’, Preview:

    ‘Drag each page’s thumbnail image from its original document to the other document.
    A rectangle encloses the other document’s thumbnails when you drag over them. If you don’t see a rectangle, the pages won’t be included in the PDF file, but they do appear in the other document’s window.’

    There is no rectangle (a grey rounded outer rectangle around the selection-grayed thumbnail) except for the first thumbnail. All subsequent dragged thumbnails elicit no such phenomenon, and it doesn’t matter: you need only drag the incoming source thumbnail unto or overlapping the last thumbnail (in the source-doc’s thumbnail-column). You won’t see any outlining rectangle to show you have properly overlapped—a violation of Apple’s user-interface directives—you simply have to visually guide the source thumbnail over the target thumnail so that they visually appear to overlap. Then you can release the button. It will drop into place below, exactly the same visually as the non-working drag-and-drop method. There’s still no special indicator to show the page has merged (or will-merge) status.

    The PDF will then truly combine them all in a single PDF when saved, but there’s nothing in the Help stating or implying this essential ‘OVERLAP’ method.

  5. ddev says:

    All I can say is that this article needs to be revised. It has taken me a couple of hours just to get these pdf’s all in one file and I was going crazy until I read the comments on how to drag and drop them. Apparently there are more ways than one to drag and drop…The directions saw drop anywhere in the thumbnail window. NOT the case you have to drop on top on of each pdf as if you wer stacking them on top of each other!

  6. Debbie says:

    Thanks for including in the notes the “special” drag and drop (where you place the page on top instead of below the current page). I had started getting crazy…

  7. Sandra Bolton says:

    How do I know if I have mountain lion or tiger or monkey…..All I know is I spent days trying to figure out my new iMac Not so easy.
    My Microsoft PC sent PDF’s and large files with no problem. Attach and click send. No problem. NOW I have huge problems with iMac Files will not send.

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