Dear Zhimao Ye, It might be a problem with the path if your machine is running Windows with One drive. Try to install mirprimer2 directly on the local harddrive (C:)
Dear Firoozeh, It seems that new versions of Windows interfere with the way miRprimer closes down. It does not afffect the calculations of the primers. However, I have uploaded a new version that should work. Best, Peter