When there is a problem in file system, e.g. the disk is full, the file system is overloaded, USPEX could have a problem in writing these *.mat files correctly, and meet a message during the calculation like:
???Error using ==> load Unable to read MAT file /home/USPEX/Current_POP.mat File may be corrupt.
When you meet an error with a corrupt *.mat file, please recover the broken *.mat file with the backup one, delete the matfilelocker file, then restart the calculation. Unfortunately, when the backup *.mat file is empty or also corrupt, you have to restart the calculation with a generation pickup.