modelsim仿真出现的错误

Modesim仿真出现的错误
# ** Warning: (vsim-WLF-5000) Waveform log file vsim.wlf currently in use.
# File in use by: haohao  Hostname: hao  ProcessID: 1164
#           Attempting to use alternate file "./wlfth4n9zg".
# ** Warning: (vsim-WLF-5001) Could not open waveform log file vsim.wlf.  Using ./wlfth4n9zg instead.