This has a lot of detail and images but it was made for people tying to install SWI-Prolog for the first time.
This page was last checked/updated on December 11, 2023.
Google Chrome was used in the process of making this. Some of the more specific steps related to downloading the executable (steps 7 and 8) will be different based on Internet browser but the concept remains the same.
While this uses the development version of the software as an example, the steps are almost identical for the stable version. The reason the development version is demonstrated is because if you have a bug and seek assistance on the forum you might be asked to upgrade to the latest development version.
Also Microsoft makes it hard to install applications that it doesn’t consider secure, this is evident as shown in step 9 where clicking on
More info is not a customary step when installing software.
Note: SWI-Prolog does not require the previous version be uninstalled.
Using an Internet browser navigate to SWI-Prolog home page: https://www.swi-prolog.org/
This will take you download page: SWI-Prolog downloads
This will take you to SWI-Prolog development downloads page: SWI-Prolog downloads
Binariesfind the (64-bit) version.
b. If you want to check out the release notes for the version they can be found here.
c. Click on the (64-bit) version.
For this example it currently is SWI-Prolog 8.5.3-1 for Microsoft Windows (64 bit)
For the notification page (Note the version numbers are different in the screen shot than the rest of the example because the image was taken for an edit to this post).
Note: If you have previously downloaded the SWI-Prolog Windows executable a dialog will not appear asking for a directory, just move onto step f.
Save Asdialog will on Windows.
b. Select a directory and click
c. In the lower left of the Internet browser screen a dialog will appear with the name of the file
d. Click on the and select
e. Move onto step 8.
f. If the dialog does not appear then go to the Downloads directory, e.g.
C:\Users\<User>\Downloadsreplacing <User> with the current user.
g. Right click on the file name and select
A Windows security dialog should appear
Windows Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.
Microsoft Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.
More infoto reveal the option to run the executable to install SWI-Prolog
This will start the installer and Windows will prompt you to elevate to admin.
This will open a User Account Control dialog (Sorry for not getting an image, would have to disable some security features to get it).
Note: If you do not see a
User Account Controldialog then use
Alt+Tabto rotate through the windows until you see it.
This will start the install wizard.
17 a. If during the install you get a dialog noting
Error opening file for writing: ...
Check to make sure you do not have an application with a lock on a file that includes the installation path, e.g.
C:\Program Files\swipl. Typical applications are SWI-Prolog, Windows File Explorer, editors such as VSCode, etc. After clearing the lock click
Retry. If you can not find the lock then a reboot is necessary.
To start SWI-Prolog
In lower left click on start button
Then at top of dialog
This will start SWI-Prolog console
For daily builds see: Download daily builds for Windows
How to uninstall SWI-Prolog.
Note: SWI-Prolog does not require the previous version be uninstalled. If a previous version is installed then during the install an additional dialog will appear asking if you want to uninstall the previous version. You can answer either
No depending upon your preference; the install should complete successfully either way.
- Using Windows File Explorer navigate to
- Click on
User Account Controldialog click
NB The directory should be either empty or have only a few files left in it. During this example the only file left was