I have tried to increase the space in my C drive to avoid the issue of memory, in case if the error is because of memory. However, it does not helped and I ended up with the same error again.
By memory, we mean the RAM of your computer, not the space available on your hard drive.
If you don't have enough RAM to run the computation, there is not much you can do except for:
- using lower resolutions for the BEM surfaces (e.g. ~500V) and the cortex surface (~5000V)
- using a different computer