gpuArray: CUDA ERROR ALREADY MAPPED

I was trying to use gpuArray, for instance with the following Matlab provided example:

X = rand(10, 'single');
G = gpuArray(X);
classUnderlying(G)   % Returns 'single'
G2 = G .* G;         % Performed on GPU
whos G2              % Result on GPU

But Matlab gives this error message. I checked online, it means the resources already mapped, which does not tell me much. How should I fix this? Previously I had no problem using gpuArray on my matlab. Thank you!

Error using gpuArray
An unexpected error occurred during CUDA execution. The CUDA error was:
CUDA_ERROR_ALREADY_MAPPED

[Walter Roberson]

Are you attempting to use gpuArray within parfor or spmd workers?

Did you try exiting MATLAB and restarting it?

[Matt J]

Do you have multiple graphics cards installed?

[Matt J]

Have you been using any non-MATLAB GPU applications?

[Walter Roberson]

Or multiple MATLAB sessions each of which uses the GPU ?

[Grace Gu]

Thank you. I did not try to use gpuArray within parfor or spmd workers. Restarting Matlab did not work. I do have 2 GPUs installed. I have used feval and GPU application too before. I plan to reinstall CUDA tomorrow, and see whether that works.

[Grace Gu]

Just now I reinstalled CUDA and it is fixed!