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Version 3.0 is out!!!
For Mac OS 10.5 and 10.6 "Snow Leopard" and higher - INTEL ONLY!





NEW VERSION 3.0 by clicking here


Please note:
Older Registration Keys have expired with this version 3.0.
See the Release Notes.

For OS 10.4 users:
download older version Split&Concat (v. 2.5)



Localized for
English, Dutch, French, Italian
Spanish and German language


Please do NOT use the Windows FAT format for your output drive if you concat files!
The FAT format has a file size limitation of 4 GB. Your joined files (movies etc.) will NOT be complete!
Instead always use the HFS+ format for your Output volume.

Version 3.0

Version 3.0 released on September 5, 2009.

Version 2.5

Version 2.5 released on April 2, 2006.

Since version 2.1: automatic Par and Par2 file creation.

Since version 2.1 Par2 and Par archive creation has been added for a set of files in a specified folder (sponsors only). The program now also can be used as an easy GUI to make Par2- or Par- files for any given set of files (and not only for the split parts that result from a Split process as in version 2.0 of the program). This function was added after several requests from users. This option is an extra bonus for the program's sponsors, to encourage the use of Par files on the Internet for recovery of missing or corrupted file parts.

In version 2.2 a block size option for Par 2 was added. In version 2.1 it was not yet possible to set the block size for Par2 files (as some users have correctly indicated). This indeed seems to be an important option. Starting with this version a check is built in the program to see if newer versions of the program have been released.

Split&Concat works closely together with Gerard Putter's MacPAR DeLuxe which program you can use for the processing of the Par- or Par2 archives created by Split&Concat.

Downloads of older versions of the program for users of older Mac OS systems:

Please note that older versions of the program do not have the same functionality as the new function! E.g. they might not have Par or Par2 functionality or international language support.


In Internet newsgroups large files often are split into smaller parts since messages can not be of more than a certain size to be able to post them in newsgroups.

For that reason you can find often binary files that are split in parts like filename.mp3.001, filename.mp3.002, filename.mp3.003 etcetera. It is possible to put these parts together using commands in the Terminal yet not everybody is handy with that.

That is why I decided to create a small utility with the OS X interface that makes it easy for people to split large files to be uploaded, or to put together split files downloaded from the Internet.

Of course, you can also use this program to split or recombine files that are too large e.g. to be put on one CD.


Starting with the Version 1.5, the program will warn you if you try to process a file that contains a "resoure fork", or if you attempt to split a Mac OS X program (which in reality if a folder containing files).

This is because the program uses Unix commands ("cat" and "split") to perform its job. That means that

In these cases you are adviced to first place the file on a disk image (using Disk Copy, or Toast etc.), then compress the disk image (convert to compressed) and then split the (compressed) disk image file with Split&Concat. If you then concat the split parts of the disk image file, the resulting file will contain an exact copy of the original file.

Still to do:

What I want to improve in the next version of the program

Splitting files

Just choose "Split" and the program will ask you to choose a file. The result (the splitted files) will be placed in the same folder as the original file by default. You can select another Output Folder by checking the CheckBox. If you want to use Drag and Drop and select another Output Folder, the best thing to do is first to open the program, then to select the CheckBox and then to drag and drop.


You will be asked for the size of the files to be split. You can choose a file size in Megabytes or kilobytes. The program limits the number of split files to a maximum of 500.

Please note that the file to be split MUST have a FILE EXTENSION (like .mp3 or .avi) otherwise the program will warn you and quit, in which case you must add a valid file extension to your file.

If there exist already files with that filename and an extension ".001" in the directory, then the program will ask you if you want to delete these older split files.

Concatenate (recombine) split files

Just choose "Concat" and the program will ask you to choose a file. The result (the assembled and joined file) will be put in the same folder as the originating split parts by default. You can select another Output Folder by checking the CheckBox. If you want to use Drag and Drop and select another Output Folder, the best thing to do is first to open the program, then to select the CheckBox and then to drag and drop.

Please note that the files to be concat MUST have TWO FILE EXTENSIONS, one extension indicating the type of the file (like .mp3) and the other extension indicating the part number (like .001 or .0aa). E.g. filename.mp3.001 The program will warn you and quit if the name of the file doesn't meet this condition.

Note that it is not important which file you choose, e.g. number .004 or .005 or any file of the split files will do.

Since version 1.0b2:
The program now will skip any PAR files (like .PAR, or P01) and not include them in the combined file.

Drag and Drop (since version 1.0b5):

The most easy way to split or concat is just to drag and drop the file to the program icon (in the Dock, on the Desktop or in a folder).


The file that you Drag-and-drop has:



License and Disclaimer

This program is donationware. I don't accept any reliability for any damage that might have been caused to your software, files or hardware or other properties by using this program. If you don't agree to this: don't use this program. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. Split&Concat, Par and Par2 are licensed under the terms of the GNU General Public License as published by the Free Software Foundation. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA


For bug reports, comments or suggestions please contact me at

My other programs:

Split&Concat will work together also in combination with MacPAR OS X, a freeware utility for OS X.1.2 to create (or restore missing files from) PAR archives for use on Internet newsgroups. This utility doesn't support the Par2- format. Allthough some users still like the interface and this program is still being used by them, the new MacPAR DeLuxe program now offers more options (including par2 format). For that reason the MacPAR OS X program is no longer supported by me anymore.

On the use of PAR archives:

Par archives Original Par file format It seems miraculous, but it is true! You can recover lost or corrupted files from a series of parts by using recovery files, called Par files. Nowadays you see frequently the par2-format, but the original format for file recovery was Par. It was created as an Open Source project on using the Reed-Soloman algorithm for restoring missing parts of an archive. In the original Par-format it was necessary to have one Par-file (e.g. filename.p001) for each missing or corrupted part of the archive. The Par-files have exactly the same sizes as the parts from which they were construed. Only if one has sufficient Par-files it is possible to reconstruct the missing or corrupted files.

But: how is this possible? I don't believe it... this is magic!!!....

It works a bit like the checksum example given below:
Say you have the following numbers: 1 4 6 7 9 the checksum of this (i.e. in the Par file) is "27" (=1+4+6+7+9).
If let's say the "7" now is missing then we have the following: 1 4 6 9 producing a checksum of (1+4+6+9=) "20"
So, if you have the checksum file ("27") then you can reconstruct the missing file from the remaining files and the checksum ("27" - "20" =) "7".
Of course, the real calculations are infinitely more complex and elaborate, but this is to only give you some feeling of what's happening.

Why the new Par2 format?

Recently the Par2-format became popular on the Internet. It has several advantages over the original Par-format. E.g. also the corrupted, partly downloaded parts now can also be used for file recovery (so you must not throw incomplete parts away with par2!). So you don't need to have so many Par-files: if only one block of a certain file is missing or corrupt it suffices to have a small Par2-file. This in theory makes it less necessary to upload so many Par2-files as with the Par-format. However, in practice the Par2 processes are very slow. It takes much more time to create a Par2-archive or to recover from Par2-files than with the original Par-format. Also, it is a bit more complex to work with Par2 in practice. Maybe future improvements of the Par2 code will make these disadvantages compared to Par smaller. Nowadays, however, it is extremely popular on the Internet and seems to have fully taken the place of the original Par format (and some might say: unfortunately!).

History of PAR for the Macintosh platform

In 2002 I started development of MacPAR for the Macintosh platform. After my initial releases of the program I discovered that Gerard Putter (also here in the Netherlands) had exactly the same idea at the same moment. In my opinion the program that I wrote in AppleScript Studio had less possibilities and features than Gerard's program. So, since Gerard and me could very well get along I decided to withdraw support for my MacPAR version in favor of Gerards' MacPAR DeLuxe program. Since that moment I assist Gerard with working on his program. The MacPAR DeLuxe program and Split&Concat work closely together.

How can I test the Par2- or Par- archive function? What do I need?

First choose a test file and copy that in a separate folder somewhere (e.g. on your Desktop). Choose "Split" in Split&Concat and select the Option "Create Par Archive". The process will result in split parts and the accompanying Par-files. Then remove the original test file from that folder, so that only the split parts and the Par-files remain. To test then remove also one or two of the split parts from the folder. Then (after you have installed MacPAR DeLuxe) after double-clicking the Par file (named .Par or .Par2) the missing parts will be recovered by MacParDeLuxe. You can find MacPar DeLuxe here:

Release Notes

Version 2.5

Version 2.5 released on April 2, 2006.

Version 2.4.2

Version 2.4.2 released on August 19, 2005.

Version 2.4.1

Version 2.4.1 released on June 2, 2005.

Version 2.4

Version 2.4 released on May 14, 2005. Recommended update for all users.

Version 2.3.2

Version 2.3.2 released on May 6, 2005.

Version 2.3.1

Version 2.3 released on May 5, 2005.

Version 2.3

Version 2.3 released on May 5, 2005.

Version 2.2.1

Version 2.2

Released on August 20, 2004.

Version 2.1

Released on August 14, 2004. This version has the following improvements:

Version 2.02

Bug fixed: the program logged the user out when cancelling a Split process.

Version 2.01

Bugfix: the program crashed on cancelling the selection of an Output folder.

Version 2.0

Version 2.0 released on April 24, 2004. Upgrade adding new features.

Version 1.6

Version 1.5

Version 1.4

Version 1.3

Version 1.3 released on October 9, 2002. A major update:

Version 1.2
Version 1.2 released on June 13, 2002:

Version 1.1
Released on April 2, 2002. What's new in this version:

Version 1.0b5
Released on February 11, 2002. Many improvements:

Version 1.0b4
Released on January 9, 2002. Improved error checking, a.o. on "forbidden" characters in the folder path. The program now only quits on serious errors and gives only warnings at minor errors. Fixed a bug in which the program refused to quit after an error statement and had to be "forced quit".

Version 1.0b3
Released on January 8, 2002. The program now should also split and concat very large files that are bigger than 2 Gig. Several bugs fixed and code rewritten.

Version 1.0b2
Released on January 6, 2002. The program now skips PAR files (.PAR or .P01 etc.) while concatenating and no longer included them in the combined file.

Version 1.0b1
Split&Concat for OS 10.1.2 or higher was born on January 4, 2002. It has been downloaded 535 times within its first two days of existence. I asked for bug reports and suggestions, unfortunately nobody gave any positive response :-(( so I guess the program works fine :-). I only received some remarks that you can do this job easy in the Terminal. I know! But since not everybody likes this or is able to work in in the Terminal and since we have the beautiful Mac OS X quartz interface, why not have a simple program for everybody?

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