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. Ana Vilma says:

    Thank you very much! :)

    • danR says:

      Just to repeat what others say: the simple drag-and-drop method in the article does NOT work in Mountain Lion, and it’s hard to believe the anonymous author didn’t simply save his/her work and never returned to the document, if using the same updated ML as others are having the same non-fix issues with.

      After multiple test docs, I’ve confirmed what others have said. Two methods:

      1. Go to Print, and rather than print, save the document as PDF there.
      2. You MUST drag and drop each PDF thumbnail ON TOP OF or OVERLAPPING the last thumbnail immediately above in the target docs thumbnails-column. Since I’ve added a ‘Save As’ command to my menu (Which Apple stupidIy removed in ML), I don’t have to do the duplicate nonsense.

      So you’ll probably find method 1 much more convenient.

  2. HelenB says:

    I did not know this was included in Mountain Lion. What an awesome feature! Thanks for explaining how it works. :-)

  3. John says:

    Thank you so much for such an easy way to merge 2 editable PDF files. That was so very easy and free.

  4. MuffinHead says:

    Great tip – but with a slight modification. You must drop the ‘incoming’ page on top of the existing page to make sure it copies, especially if there is only one page in the destination file.

    If you just drop it into the thumbnail bar it may just show as a second document in the same ‘viewer’.

    Once you have more than one page in the destination file you should see a faint line at the bottom of the thumbnail bar – make sure you drop in new pages above that line.

    • Hans says:

      MuffinHead: Thanks for that additional info. It didn’t work for me because of this particular problem – I had only one page. You’ll know that the pages are combined into one when you see them within a collapsible/expandable title bar of the document in the thumbnail window.

      For the poster of the article. Awesome job of explaining this How To! Thanks

    • Mixa says:

      Side effect: Dropping a file on top of a one-page file produces a huge file: 15 kb + 292 kb = 4,9 Mb. But if I drop the file into the thumbnail bar below the first page, select all, print and save as pdf: 15 kb + 292 kb = 713 kb. Why the difference? By the way, batch pdf merger produces only 341 kb.

      • Stuart says:

        Yes! “print and save as pdf” was exactly what I needed. My three one-page pdf files didn’t combine into one until I did that. Thank you!

    • Diana Lee says:

      Yes, THANK YOU for adding this tip. It was exactly the problem I was having & couldn’t figure out. So frustrating. So again, thank you.

    • SusanneM says:

      Thank you MuffinHead, this did the trick, great help ☺

  5. Brett says:

    Thanks for this. Found out that you have to drag the other PDF’s inside of the original pdf in order for it to merge.

  6. Richard Roper says:

    This worked up to a point – but when I tried to save it the document reverted back to the original. I even tried duplicating then saving but even the copy just reverts back. Any help on what I’m doing wrong?

  7. Hal says:

    I have 10.8.2 and I also have the problem as state earlier. It looks fine until I duplicate or save. The files all revert back except for the duplicate. Can you help?

  8. Chazz says:

    Richard, I had the same issue. Turned out I was trying to merge two .jpegs (scanned documents) in Preview, not .pdfs.

    May or may not be your case too.

    • Maureen says:

      I found that I was trying to merge .jpegs too, but like some others have said a good work around is open all of the .jpegs in viewer and then print to PDF. They will all be merged and in PDF form instead of .jpeg. Good luck all!

  9. Sophie says:

    Step 3 says that you can drag the next pdf file into anywhere into the thumbnail window which is possible but when you have a book that’s broken into a number of different pdf files, dragging them anywhere, puts the pages in the wrong order.

  10. Michal says:

    Thanks a lot!!! I was just looking for a programme to do so :-)

  11. Terryl says:

    I’m having the same problem as Richard Roper, and I (for sure) have 10.8.2. Also can’t get an ‘incoming’ image to drop on top of the existing image (as MuffinHead described); it will only go onto the left (thumbnail) part of the screen. Even when I put it above the first (only) image there, it saves as whatever image is highlighted. Highlighting everything makes no difference – it saves as the original image. Frustrating! What am I doing wrong?

  12. Myles says:

    I’m having the same “save” problem, and I think it may be the security settings that the file embeds from Word… It looks like there are document restrictions, set as a standard in Word. Can’t seem to figure out how to reset them

  13. Chuck says:

    Didn’t work for me in Mountain Lion. It only copied the first page of the new pdf into the original one.

  14. Manny says:

    I’m having the same problem as others. I can put multiple pdf files into one “document” in preview so that I can go from one to the other. But saving them does not merge them into one. I even selected all the pages in the thumbnails section before I did a save, and it still didn’t work. When I try Duplicate, only the last page selected gets duplicated, not all of them.

    Not sure about any security settings or restrictions. The pages I’m trying to merge were forms I scanned. I didn’t set any restrictions when I scanned them.

  15. Jennifer Harper says:

    Thank you so much. I can’t believe how easy this was.

  16. Stumpweasel says:

    Brilliant, I’ve now got one doc not two but it’s on my Mac. If only the office PC network could cope with the file size via email. Guess I’ll have to find that memory stick…

  17. Kev K says:

    Thanks so much this saved me money and it is not bad as I thought. Very simple.

  18. Laura says:

    Holy crap! It finally worked! Thanks so much!

    • MartyA says:

      With all of the positive responses I am truly embarrassed because I don’t get anything. I am working with OS 10.8.2 and Adobe Reader 11.0.02.

      I had trouble finding Thumbnail which for me was,

      View/(Show/Hide)/Navigation Panels/Page Thumbnails.

      When I try to deposit the file onto anything in the Thumbnail nothing happens.

      It’s tough growing old!

  19. MartyA says:

    With my deepest apologies. I don’t know why after hours of trying I waited to submit a reply before I suspected that you all were working in Preview and not Adobe Reader.

    I think that I can learn the correct procedure. Thanks, if you were patient with me.

  20. Ray Barrick says:

    1. I had the same problem with saving the new, multi-page document. There was a security setting in the PDFs that did not allow document assembly. I was, however, able to “print” the assembled document, adn selected “PDF, Save As” (on the lower left of the print window.) I lost the links, but otherwise is OK.

    2. I see that I can annotate the PDF, but is there a way to add page numbers?

    3. Can I add bookmarks that will link sections of the document to the Table of Contents?

  21. Ram says:

    For many who are still unable to do it, I am nearly certain it is because the file is protected (as the instructions above mention at the end). I kept trying to merge some files and they kept ending up as separate files. And even the advice from muffinhead did not seem to work.

    I then downloaded a free app named PDF unlock, it unlocks PDF files that are locked for printing or merging (not password protected files that won’t even open). Once unlocked, the instructions above worked like a charm in Mac’s own Preview app where the PDF files merged as they should.
    The PDF unlock app can be downloaded here:

  22. MRM says:

    I had the same problem as everyone else. What worked for me was once I had the thumbnails all set (6 pages total) I went to Preview–> Print —> Save as —> PDF. It worked just fine. It wouldn’t let me save it, but if I went to print it and saved it as a PDF at that point it worked like a charm.

  23. Lee says:

    TYPO ??
    (2) Open the thumbnails draw

    Did you mean:
    (2) Open the thumbnails drawer

  24. Erica says:

    I am not understanding this at all. I have 10.8.3 & can’t figure it out.
    Any additional info would be helpful!

  25. Joel says:

    “This is a simple 4-click process…” that the article did not get right. Agreed with commenter MuffinHead, open the first page, then “drop the ‘incoming’ page on top of the existing page to make sure it copies” (not “anywhere” as the article says). Is it possible to fix the article or show a couple of options? It’s a shame that such a crucial detail was omitted.

  26. Michael says:

    Adding to Joel it would be nice to add that one has to use the viewer app to do that. I’ve installed Adobe Reader on my Mac and it’s determined as standard application to open pdf files. Took me a while to work out how it actually is done. Anyways, it worked perfectly without any of the above mentioned issues.

  27. Lars says:

    This is extremely frustrating. It “works”….until you save it. When you re-open it or export it, it doesn’t retain the other pages. Over 10 years ago, I briefly had a PC, and hated it. The more I know Mountain Lion, the more it reminds me of the PC. Any insight would be appreciated, although it is time sensitive and therefore probably be a little late.

  28. Peter says:

    Excellent, you have saved me heaps of time and effort. I love how simple everything is on a Mac.

  29. BILL says:

    The new version of Mountain Lion 10.8.4 blocks this procedure.
    It will let you form a multi-page pdf, but it will not let you save it as a grouped document. It will only give you the original page single page you started with.
    Just stupid there’s no Save-As command to rename the file.
    I tried Duplication, Save, Drag and Drop, all forms are now blocked.
    Plus, Adobe will not read or show pdf’s created by Preview.
    Seems to be a war going on between the companies.

    • Gianluka says:

      It actually works perfectly. You must drag&drop the extra files on top of the THUMBNAIL of the existing page to make sure it add the new PDF’s to the original one. (YOU WILL SEE A ‘PLUS ICON’ APPEAR WHEN YOU DRAG OVER IT) Then just save it. Cheers ;)

      • Kathy says:

        I would have never figured that out unless I read your comment. Thanks for saving me hours of frustration by just a drop and click :) Awesome!!!

      • Joanne Kim says:


  30. BILL says:


    Once you create the multi-page PDF document per the instructions above.
    You must do a print to safe pdf as a new document.
    When you click print, then chose the save as PDF option.
    Then you will be able to save your complete file as a new PDF.

    No other way works.

    • Nicole says:

      I thought I was the only one who was having this problem Bill! I was clicking and dragging all over the place but nothing was working!!
      Clicking ‘Print’ and then ‘Save as PDF’ was the only way I could save a multi document version, everything else was just saving one page at a time!
      Thank you BILL!!

    • Rodrigo says:

      YOU THE MAN BILL, you’re absolutely right: no other way works!

    • Mary says:

      After trolling the internet for an hour I finally found out how. Thanks Bill!

    • Sumit says:

      Thank you Bill! I have been looking for this solution for hours!!!

    • Inger Nordin says:

      Thanks – with this instruction it is working! So happy!

  31. dan says:

    thanks so much. this was incredibly helpful!!!

  32. PCJ says:

    Worked perfectly! Thank you!

  33. BW50 says:

    Seemed to work fine. I combined 4 files together (15 pages total), I just needed to add one more page from one last file, and it wouldn’t allow it. Every time I dragged it over, that last page would just float back to it’s original pdf. Any ideas?

  34. Allen says:

    Doesn’t work for me. I repeated the process 8 times and it doesn’t work. I drag the file in, save it. I open the updated file and I on have the first page.

  35. John says:

    I can’t seem to manage it (10.8.5, two one-page pdfs opened in Preview, both selected in the thumbnail sidebar, save to pdf from the print menu, reopen the document and still only one page in it–nothing works).

    • John says:

      No, sorry, doing what I just wrote *did* work. I had to make sure to select both documents in the thumbnail sidebar (shift + click) before saving (from the print menu).

  36. So easy! I love this about mac. So many hidden things that makes your life easier once you find them..

  37. Nicholas RG says:

    Fantastic; well explained and the more I use apple the more I love it ! The greatest problem is trying to find out all the good stuff tucked away in the software !

  38. Stephen says:

    Thanks for the article and to Muffinhead – the article should be clarified as it only works if you drop the incoming file on top of the destination thumbnail. However this merging procedure corrupts all the html links in both files (except for the mailto: links). So be warned.

    FYI: I’m on 10.8.5 and I used Word 2011>print>save as pdf to make the pdfs.

  39. Martin says:

    I guess things have changed since the original post. It’s October 2013 and I’m up to OS X 10.8.5 and Preview version 6.0.1. I did make a single big PDF out of several different PDFs by drag and drop but it depends on exactly what you drop and where you drop it.

    If you drop files from Finder into Preview you get separate PDF files shown in Preview. That’s not what I wanted.

    Let’s say I open PDF 1 in Preview window A, show thumbnails, and make sure I have page thumbnails, not file thumbnails. Then I open PDF 2 in Preview window B, view thumbnails, select all the page thumbnails, and drag them.

    If I drop the thumbnails into window A below the existing thumbnails I get the same result as if I drop a file from Finder. Window B closes and window A shows PDF 1 and PDF 2 as separate files.

    Instead, I dropped the thumbnails from window B so that the topmost thumbnail that I dragged partly overlapped the lowest thumbnail that was already there. That copied all the pages from PDF 2 into PDF 1, after the existing pages.

    Now you want to Save As so you don’t overwrite PDF 1. There is no Save As in the menu. You get it by using Duplicate and then Rename.

  40. William Sievers says:

    I’m using 10.9.1 and they’ve totally messed up what used to be an easy to use feature. Documents don’t want to combine anymore. All the “improvements” in Pages, Preview and Numbers seem to be straight from the software demons from hell whose sole mission is to frustrate formerly happy Apple users. Thanks to the person who suggested using the Print as PDF feature because that finally let me combine added pages into one document. CAN WE START A PETITION TO BRING BACK “SAVE AS”?

  41. 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.

  42. bernie says:

    thanks heaps . That works well .

  43. Tracie says:

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

  44. 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.

  45. 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!

  46. 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…

  47. 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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