Parpool fails to run in between other lines of code

The following code returns the error below in MATLAB R2020b, Windows 10.

However, after restarting MATLAB and running only ppp=parpool(4) on a fresh script, it works. Has anyone ever experienced such a thing? I need to perform same operation on 6 other climate variables, so speed is of the essence. Running a normal for-loop is slow; therefore, is very discouraging.

Precips = ".\ECMWF_Datasets\cru_ts_4.05\data\pre\cru_ts4.05.1901.2020.pre.dat.nc"
Times = ncread(Precips, "time");
Times = double(Times) * 24 * 3600; 
ref_date = datestr('1900-01-01 00:00:00.0');
Times = datetime(Times,'ConvertFrom','epochtime','Epoch',ref_date);
XXX = ncread(Precips, "pre"); % 720 x 360 x 1440

ppp = parpool(4);   % returns the error below
parfor i = 1:length(Times)    
    "Perform some operations on XXX"
end
delete(ppp);

Error using parpool (line 149)

Parallel pool failed to start with the following error. For more detailed information, validate the profile 'local' in the Cluster Profile Manager.

Caused by:

Error using parallel.internal.pool.InteractiveClient>iThrowWithCause (line 678)

Failed to start pool.

Error using parallel.Job/submit (line 355)

Unable to use a value of type cell as an index.

Answer 1

[Raymond Norris]

I'm guessing it's something to do with your environment. When I test with example.nc, it works fine. Is your code in a script or a function? If a script, save it as a function and rerun your code to see if that shields it from the error.

[Richard Fiifi Annan]

Hello @Raymond Norris, thanks very much for the response. You're right, the culprit was some directories which I had added to MATLAB's path at the beginning of the script. I just had to comment those lines out.