Install SWI-Prolog development version on Windows 10

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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.

1. Using an Internet browser navigate to SWI-Prolog home page: https://www.swi-prolog.org/

2. Mouse over Download
   

   
   
   

3. Click SWI-Prolog
   This will take you download page: SWI-Prolog downloads

4. Under Available versions click Development release
   
   This will take you to SWI-Prolog development downloads page: SWI-Prolog downloads

5. a. Under Binaries find 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)

6. 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).
   

   
   
   a. Select I understand
   b. Click Download swipl-8.1.12-1.x64.exe

7. 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.
   a, A Save As dialog will on Windows.
   

   
   
   b. Select a directory and click Save
   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 Open
   
   e. Move onto step 8.
   f. If the dialog does not appear then go to the Downloads directory, e.g. C:\Users\<User>\Downloads replacing <User> with the current user.
   g. Right click on the file name and select Open

8. A Windows security dialog should appear
   

Windows Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.

or

Microsoft Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.

9. Click More info to reveal the option to run the executable to install SWI-Prolog

10. Click Run anyway
    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 Control dialog then use Alt+Tab to rotate through the windows until you see it.

11. Click Yes
    This will start the install wizard.

12. Click Next

13. Click I Agree

14. Click Next

15. Click Next

16. Click Next

17. Click Install

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.

18. Click Finish

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To start SWI-Prolog

In lower left click on start button
Then at top of dialog

click SWI-Prolog

This will start SWI-Prolog console

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For older versions there are
HTML pages
current stable version
older stable versions

and directories
Index of /download/stable/bin
Index of /download/devel/bin

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For daily builds see: Download daily builds for Windows

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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 Yes or No depending upon your preference; the install should complete successfully either way.

1. Using Windows File Explorer navigate to C:\Program Files\swipl
2. Click on Uninstall.exe
3. For User Account Control dialog click Yes.
   
   4 Click Uninstall
   
   
4. Click Close
   NB The directory should be either empty or have only a few files left in it. During this example the only file left was C:\Program Files\swipl\boot64.prc