Partial Least Squares (PLS) extension does not run in SPSS Statistics 25, error: Extension command PLS could not be loaded

You have not installed the special requirements to run PLS. Please see the info section on the dialog:
"Special setup is required to run the Partial Least Squares Regression procedure. Click Help and see the Prerequisites section for details".



If you click on Help you will see below text:

Prerequisites

The Partial Least Squares Regression procedure is a Python extension command and requires IBM® SPSS® Statistics - Essentials for Python, which is installed by default with your IBM SPSS Statistics product. It also requires the NumPy and SciPy Python libraries, which are freely available.

Windows and Mac Users

For Windows and Mac, NumPy and SciPy must be installed to a separate version of Python 2.7 from the version that is installed with IBM SPSS Statistics. If you do not have a separate version of Python 2.7, you can download it from http://www.python.org. Then, install NumPy and SciPy for Python version 2.7. The installers are available from http://www.scipy.org/Download.

To enable use of NumPy and SciPy, you must set your Python location to the version of Python 2.7 where you installed NumPy and SciPy. The Python location is set from the File Locations tab in the Options dialog (Edit > Options).

Worked out Example to get PLS to run in SPSS Statistics version 25 on a Windows 64 bit computer.

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Windows 64 bit: The 64-bit Python download link is https://www.python.org/ftp/python/2.7.13/python-2.7.13.amd64.msi

Save the file python-2.7.13.amd64.msi to your desktop
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NOTE for Windows 32 bit: If you have a Windows 32 bit computer use below link and download Python 2.13.msi
https://www.python.org/downloads/
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DO NOT use the 32 bit Python on a Windows 64 bit system. Use 2.7.13.amd64.msi instead
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Install 2.7.13.amd64.msi for 64 bit Windows. Click on the downloaded file python-2.7.13.amd64.msi and start the installation


Recommended is to install to default directory C:\Python27



2. Verify the content of C:\Python27\Scripts folder
Once the installation of Python 2.7 is finished got o path C:\Python27\Scripts and verify if you see pip.exe, as we will need this later.



3. Download Numpy and Scipy from

http://www.lfd.uci.edu/~gohlke/pythonlibs/

Scroll down the page to find the required packages:
3.a)


numpy-1.13.1+mkl-cp27-cp27m-win_amd64.whl

3.b)


scipy-0.19.1-cp27-cp27m-win_amd64.whl

4. Use the pip command in Python 2.7 to install the Numpy and Scipy

For Numpy the command is:
pip install C:\numpy-1.13.1+mkl-cp27-cp27m-win_amd64.whl
For Scipy the command is:
pip install C:\scipy-0.19.1-cp27-cp27m-win_amd64.whl

To do so open an Administrator command prompt on your windows 64 bit machine and change directory to C:\Python27\Scripts. Run above commands. If it was successful you should see text like on below example

**************Example***************************


Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\IBM_ADMIN>cd..

C:\Users>cd..

C:\>cd python27\scripts

C:\Python27\Scripts>pip install C:\numpy-1.13.1+mkl-cp27-cp27m-win_amd64.whl
Processing c:\numpy-1.13.1+mkl-cp27-cp27m-win_amd64.whl
Installing collected packages: numpy
Successfully installed numpy-1.13.1+mkl

C:\Python27\Scripts>pip install C:\scipy-0.19.1-cp27-cp27m-win_amd64.whl
Processing c:\scipy-0.19.1-cp27-cp27m-win_amd64.whl
Requirement already satisfied: numpy>=1.8.2 in c:\python27\lib\site-packages (fr
om scipy==0.19.1)
Installing collected packages: scipy
Successfully installed scipy-0.19.1
****************

5. Set External Python 2.7.13 to be used in Statistics 25
Open Statistics 25 release and click on Edit – Options – file locations tab. Edit the section: Python 2.7 Location and browse to your external Python 2.7 installtion directory.


6. Run your PLS command.

As a test use the below one for sample file Employee Data.sav



PLS minority MLEVEL=N REFERENCE=LAST WITH salary salbegin
/CRITERIA LATENTFACTORS=5.

PLS will then run successfully