How do I fix this error on Matlab startup? java.lang.​IllegalArg​umentExcep​tion: File migratePref.txt should only contain 'T' or 'F'!

This error also appears when using the Application Compiler

java.lang.IllegalArgumentException: File migratePref.txt should only contain 'T' or 'F'!
java.lang.IllegalArgumentException: File migratePref.txt should only contain 'T' or 'F'!
  at com.mathworks.services.Prefs.readMigrateFlag(Prefs.java:2196)
  at com.mathworks.services.Prefs.createTwoWayMapPrefsSettings(Prefs.java:375)
  at com.mathworks.services.Prefs.<clinit>(Prefs.java:213)
  at java.lang.Class.forName0(Native Method)
  at java.lang.Class.forName(Class.java:264)
  at com.mathworks.util.PostVMInit$StartupClass.init(PostVMInit.java:161)
  at com.mathworks.util.PostVMInit.perform(PostVMInit.java:237)
Warning: Initializing MATLAB Graphics failed.
This indicates a potentially serious problem in your MATLAB setup, which should be resolved as soon as possible.  Error detected was:
MATLAB:load:unableToReadMatFile
Unable to read MAT-file C:\Users\BrendanM\AppData\Roaming\MathWorks\MATLAB\R2018a\matlabprefs.mat. File might be corrupt. 
> In hgrc (line 163)
  In initprefs (line 11)
  In matlabrc (line 94)

[Walter Roberson]

I suggest moving aside C:\Users\BrendanM\AppData\Roaming\MathWorks\MATLAB\R2018a\matlabprefs.mat and trying again.

[uuu]

I resolved those two errors by simply removing those two files, now I have the error

 fl:filesystem:SystemError

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/302118-error-run-matlab-on-computer-cluster-multithreading-error#answer_233976

Answer 1

[Kautuk Raj]

The error message you are encountering indicates that the startup preferences for MATLAB are invalid or corrupt.

I suggest you try to to recreate the preferences currently in place on your system using the following article on the MATLAB Answers forum: https://www.mathworks.com/matlabcentral/answers/99625

Try following the steps outlined there, and after doing so launch MATLAB again to check if it resolves the error.