To regenerate your MATLAB preferences, do the following:
1. Locate the MATLAB preferences directory for your user account.
The default location of the preferences directory is at the following location:
/home/$USER/.matlab/R2021a (on Linux)
You can also run the following command in the MATLAB command prompt in order to locate your preferences directory:
This is where your "matlab.prf" file is located. Your path may be different depending on how your system is setup. The preference directory may be hidden in some operating systems.
2. Make sure that MATLAB is closed and rename the preferences directory of your current MATLAB version, for instance rename R2015b to R2015b_old. Then create an empty folder with the original name, in this case R2015b. Creating this empty folder will prevent MATLAB from importing a preference directory from a previous release.
3. Restart MATLAB. MATLAB will recreate preferences files in the empty preferences directory that was created in step 2. If this does not address the issue that you hoped it would, it is possible to restore your preferences by deleting the newly created directory (R2015b) and renaming the R2015b_old directory back to its original name: R2015b.