synapsen

Manual

Sat, 22 Aug 2026 11:36:33 +0800

The manual (version 5.x) covers, besides the usual description of the functions and features, the new modules “knowledge graph” and “timeline” as well as explanations on how to install the app on different operating systems (such as macOS, Windows, Linux) as well as some hints on note-keeping and its historical background.

Updating synapsen

Fri, 21 Aug 2026 13:01:04 +0100

Before each update of synapsen you should backup your literature data! To update synapsen from older versions to the current version, first copy the update installer to your hard disk and then start it.

macOS: the disk image updateSynapsen5.dmg (approx. 370 MB). It is signed and notarized by Apple. Open it with a double click; two steps are needed inside:

Drag Synapsen.app onto the Applications shortcut next to it and confirm the replacement. No installer can do this for you: since version 14, macOS lets only the Finder replace an existing application.
Then launch updateSynapsen5.app. It brings the database up to date and places the manuals and auxiliary files.

Update Synapsen for macOS

Download Synapsen

Sat, 15 Aug 2026 11:39:46 +0100

Here you can download an unregistered, slightly limited, freely distributable version of synapsen. For registration and removal of the limitation please consider these license information.

Update from older versions already installed: If you want to upgrade from an older version of synapsen to the current version, please follow these instructions.

Important: synapsen can be used with all popular operating systems. Only the so-called Java Virtual Machine (JVM), at least at version 26 (Java 26) must be installed on your system in order to install the card-catalog. You can load the JVM directly from Oracle or from adoptopenjdk.

Problem during Installation

Wed, 02 Jan 2019 18:49:42 +0100

Sometimes the installer routine of synapsen fails, displaying a message like this:

This somehow cryptic message means the installer found a wrong version of Java on your system. Please make sure you have a Java Virtual Machine (JVM) available at least at version 26 (Java 26). You can load the JVM directly from Oracle.

Also important: Currently, synapsen does not support Java 21 or older. Please use Java 26 or newer.

Working directory

Sun, 23 Dec 2018 13:01:04 +0100

macOS

Under macOS the working directory of synapses is located in this directory:

~/Library/Application\ Support/Synapsen/

Where ~/ stands for the user-home directory, e.g. /Users/anton/, if your user is called “anton”. In this case you switch to the syndb folder via the terminal with

cd ~/Library/Application\ Support/Synapsen/
ls -la syndb
zip -r ./2018-12-31-backUp-Synapsen.zip syndb

to view the database and make a backup copy if necessary.

Windows und Linux

Under Windows and Linux, a separate folder called Synapses is created in the program directory (or where you specify it during installation). Here you will find the program files, but also the database with the literature data, in the subdirectory syndb.

Gallery of Screenshots

Sun, 23 Dec 2018 11:39:46 +0100

Here you’ll find some screen shots of the program and its features and functions. Among the features shown are, e.g., the bibliography function, the printing interface including the feature to print ‘real’ index cards on paper, and, last but not least, the new features of version 5.0, i.e. the timeline tool and the mind map.

About Synapsen

Sun, 23 Dec 2018 11:39:39 +0100

Synapsen is a digital card index or reference organizer (developed since 1996), which is to say a storage system on the basis of an electronic literature database that enables the management of bibliographies. However, in contrast to normal literature management software, synapsen offers a very distinct advantage: with catchwords entered by the user, the program connects individual cards automatically and creates not only a network of cards whose relation to each other might have been forgotten, but also creates completely unexpected connections and relations between individual entries. synapsen is therefore not only for electronic literature management, but also a helping hand when writing scientific texts, which participates in communication with the author in order to augment lines of argumentation and the generation of ideas.

Licensing

Sun, 23 Dec 2018 11:39:39 +0100

Since synapsen follows the ShareWare-concept, it may – except for the personal registration – be copied. Synapsen has two various modes, one for unregistered users testing the software and the other for personally registered users who wish to maintain a professional literature management system. The modes can be distinguished by a small difference: The unregistered mode has a limited search function and a limited list of links: only a portion of the theoretically unlimited list of links will be shown. This effect will only limit your work if you have already spent a large amount of time working with synapsen and have gathered so many entries that the amount of hits rises above the limit.

Startup problem: No program window visible

Wed, 14 Nov 2018 11:36:33 +0800

Although you have started the program as usual, wait in vain for the synapsen main window to open. Nothing happens, not even an error message? - The reason is: the window has opened, but not in the visible part of the screen, for whatever reason. In these, however, you can easily direct the program in again by doing the following:

Finish synapsen if it is still active somewhere in the background.

Synapsen no longer displays data

Wed, 14 Nov 2018 11:36:33 +0800

After updating synapsen, the program can still be started, but each of the slips of paper only shows the hint “Links into void”. The problem is that the internal database has not been updated correctly. You can fix this by executing the update installer.

Editing a person card

Mon, 12 Nov 2018 11:36:33 +0800

The operating logic of the person card deviates slightly from the bibliographic entries. If you close the note with the “Close” button, the data will be saved; if you close the window with the window close button, the data will not be saved:

Backup

Wed, 01 Nov 2000 11:36:33 +0800

To save the data that you have entered into the internal synapsen database so far, it is sufficient to call the backup routine there via the menu item Info|Database. This creates a file with the extension .hsql, which contains all data in the format of a hsql database. Or, to be on the safe side, it is recommended to create an archive from the directory “syndb” in the working directory of synapsen via “zip” or a similar packing program to store it in a safe place.

Show error messages

Wed, 01 Nov 2000 11:36:33 +0800

If synapsen do not work properly on your system, it is essential to take a look at the (error) messages of the program. First, stop synapsen if it is still active somewhere in the background. Then call synapsen in a different way than usual:

Windows

Call up the entry “Card box with messages” in the start menu of synapsen. A command line window opens in the “Task Bar”, which you can click on. Messages such as: “Database is addressed under Windows…” will appear there. Now work with the program as you are used to and pay attention to the (error) messages that are displayed in the command line.

Startup problem with error message: »Connection to internal server failed«

Wed, 01 Nov 2000 11:36:33 +0800

After updating synapsen an error message “Connection to internal server failed” may occur. The program will abort at startup. The problem is that the internal database cannot be accessed correctly. A number of reasons can be responsible for this.

The most common reason is that the internal database has not been updated by synapsen. You can fix this by executing the update installer.

It is also possible that you do not have sufficient access rights to the working directory of synapsen. This is a problem that often occurs under Windows 7 or Windows Vista, but also on Linux systems. The solution is comparatively easy: Simply set the permissions manually so that you as the user have read and write access to the syndb directory in the synapsen folder. You may also need to turn off Windows UAC.

synapsen

Manual

Updating synapsen

Update Synapsen for macOS

Download Synapsen

Problem during Installation

Working directory

macOS

Windows und Linux

Gallery of Screenshots

About Synapsen

Further Reading

Articles and books concerning ‘card indexes’ und ‘reference management’, historically, theoretically, practically.

Licensing

Startup problem: No program window visible

Synapsen no longer displays data

Editing a person card

Backup

Show error messages

Windows

Startup problem with error message: »Connection to internal server failed«