Why can't I save my MATLAB path on Windows?

I use MATLAB on a Windows computer. When I try to execute the function 'savepath' in MATLAB, my path is not saved and I receive the following warning:

>> savepath
Warning: Unable to save path to file 'C:\Program Files\MATLAB\R2023a\toolbox\local\pathdef.m'. 
You can save your path to a different location by calling SAVEPATH with an input argument that specifies the full path.
For MATLAB to use that path in future sessions, save the path to 'pathdef.m' in your MATLAB startup folder.

When I try to save the MATLAB path from the 'Set Path' dialog, I get the message:

MATLAB cannot save changes to the path.
The path file, pathdef.m, might be read-only or might be in a directory for which you do not have write access.
You can save pathdef.m to a different location. In order for MATLAB to use that pathdef.m
in future sessions, you need to save it in your MATLAB startup directory (the directory from which you start MATLAB).
Would you like to save pathdef.m to another location?

Answer 1

[MathWorks Support Team]

The system-wide pathdef.m. file containing the MATLAB search path is located in the MATLAB installation folder, which typically is:

C:\Program Files\MATLAB\RXXXXx\toolbox\local\pathdef.m

When the default installation folder (C:\Program Files) is protected by Windows User Account Control (UAC), standard users do not have write access to pathdef.m. This helps prevent accidental or unauthorized changes to the system-wide MATLAB path.

Note that it is not mandatory to save the MATLAB path for it to take effect in your current MATLAB session. You can make temporary changes to the MATLAB path which will persist for your current session. All changes take effect immediately.

In the 'Set Path' dialog, you add and remove paths interactively and just "Close" the window without clicking "Save":

For the programmatic approach, use the 'addpath' or 'rmpath' functions without calling 'savepath' at the end. See: https://www.mathworks.com/help/matlab/ref/addpath.html

Permanent Solution for Future MATLAB Sessions

If you wish to have a permanent solution that automatically sets your custom MATLAB path for future MATLAB sessions, consider one of the following workarounds:

• Option 1: Run MATLAB as an Administrator
• Option 2: Add folders automatically at MATLAB startup (recommended)
• Option 3: Add folders automatically at project startup
• Option 4: Save pathdef.m in your MATLAB startup folder (not recommended)

Option 1: Run MATLAB as an Administrator

On some systems, starting MATLAB as administrator may be sufficient to get write permission to the system-wide pathdef.m.. To run MATLAB as an administrator, right-click on the MATLAB icon and choose "Run as administrator".

NOTE: If you are on a shared computer, overwriting the system-wide pathdef.m is not recommended, as it will permanently set the path for all MATLAB users on that system, unless they have configured MATLAB to use a personal copy of pathdef.m. Consider using Options 2-4 instead.

Option 2: Add folders automatically at MATLAB startup (recommended)

One easy solution is to create a startup.m file containing 'addpath' commands and save it in a folder on your MATLAB path (e.g. the userpath, which is typically "C:\Users\<USERNAME>\Documents\MATLAB").

This can be achieved by typing:

>> edit(fullfile(userpath,'startup.m'))

on the MATLAB Command Window. Then, on the "startup.m" file, write:

addpath('desiredFolderFullPath')

You would still not be able to use the 'Set Path' dialog or the 'savepath' command, but the startup.m file provides a lot of flexibility to implement any user-specific customization for your MATLAB sessions. Refer to the following documentation for an overview of startup.m and other more advanced ways to specify MATLAB startup options:

• User-defined startup script for MATLAB
• Add Folders to the MATLAB Search Path at Startup

Option 3: Add folders automatically at project startup

A great option for team collaboration is to add folders to the MATLAB path on a project basis using MATLAB Projects and Simulink Projects. Learn more about project paths here:

• Automate Startup and Shutdown Tasks - MATLAB Projects 
• Specify Project Path - Simulink Projects  

Option 4: Save a copy of pathdef.m in your MATLAB userfolder (not recommended)

WARNING: If you intend to use multiple MATLAB releases, do not place "pathdef.m" in your userpath.

"pathdef.m" is unique to each release, whereas the default userpath containing "startup.m" is shared across all releases. Following the workflow outlined below may result in loading the same "pathdef.m" file for every release, leading to a corrupted MATLAB session.

If the ability to use the 'Save Path' dialog or the 'savepath' command is a priority, you can save a personal copy of pathdef.m in your MATLAB userpath folder. By default, the MATLAB userpath folder is the Windows user directory, where each user has full read/write access. You can use the 'savepath' command as shown below to save copy of pathdef.m to the user directory:

>> cd(userpath)
>> savepath pathdef.m

Below are the steps to change the location of pathdef.m using the 'Set Path' dialog:

For more information, see:

• How can I configure a user-specific MATLAB path on a shared computer?

[K E]

Even when I 'Run as Administrator' (#1), I still can't save paths in R2015a.

[Abhishek Pandey]

Hi,

This probably means that you do not have administrator rights in your system. You basically need permissions to edit the pathdef.m file which is in your Windows directory.

Hope this helps!

- Abhishek

Answer 2

[yunhui zhou]

Please note the following words in error message: " You can save pathdef.m to a different location, In order for MATLAB to user the pathdef.m in future sessions, you need to save it in your MATLAB startup directory (the directory from which you start MATLAB). Would you like to save pathdef.m to another location?".

Just copy and save pathdef.m to your user directory (for example "C:\Users\<Your_Name>\Documents\MATLAB") and you can save your path without messing the MATLAB path for other users of your computer.