Why do I get the error "Unrecognized function or variable 'ctfroot'" when running "MATLABWeb​AppServer.​exe"?

Why do I get the error "Unrecognized function or variable 'ctfroot'" when running the Development version of MATLAB Web App Server - "MATLABWebAppServer.exe"?

Here is a screenshot of the exact error:

Answer 1

[MathWorks Support Team]

This error message is caused because the MATLAB file 'ctfroot.m' has not been properly extracted when the Development Version of MATLAB Web Server has been installed.

The first step to take to resolve the issue is to locate the folder "compiler" in the MATLAB Runtime cache directory. MATLAB Runtime cache can be found by following instruction in 

How to Clean the MATLAB Runtime (MCR) Cache? - MATLAB Answers - MATLAB Central (mathworks.com)

For example, for R2024a your "compiler" folder might be

C:\Users\<username>\AppData\Local\Temp\<username>\mcrCache24.1\MATLAB0\toolbox\compiler

The "compiler" folder should contain the 'ctfroot.m' file. 

If this file or one of the folders above are missing, you can try to force extracting these files again by following the steps below:

        1. Run the 'MATLABWebAppServer.exe' and close the 'MATLABWebAppServer.exe'

2. Delete the toolbox folder from the MCRCache24.1/MATLAB0 directory

3. Run the' MATLABWebAppServer.exe' again

The toolbox folder will be then extracted again and the issue should disappear.

[Image Analyst]

The same thing happened to us. Running fine with R2020a, then all of a sudden it quite working with this error. We have no idea why. Tried running setup.exe for the main MCRinstaller (we have the full 2 GB installer rather than the WebAppServer that downloads the 2 GB of software) and it didn't fix it. In Windows 10, we had to actually

1. Go to the c:\Users\<username>\AppData\Local\Temp\<username> folder and
2. Delete the mcrCache9.8 folder, and then
3. Run setup again.

That fixed it, at least for now.