When a user tries to run the HyperMesh script from SimLab, the 'ALTAIR_HOME' env will be changed and it will conflict with the HyperMesh installation path. The conflict can be avoided using the below methods. 1. Using the following Python code CODE: #import subprocess module is used for accessing the system commands import subprocess ,os #To avoid the conflict between the SimLab and HyperMesh installation path store the ‘ALTAIR_HOME’ env in a python variable and clear the env. Altair_Home = os.environ["ALTAIR_HOME"] os.environ["ALTAIR_HOME"]='' #Store the tcl script path and HyperMesh installation path in a python variable. TCLScript = "./HM_Script.tcl" hmBatchLoc = "./../hwdesktop/hm/bin/win64/hmbatch.exe" #To start HyperMesh and execute the tcl script in batch mode use the below codes Arg= hmBatchLoc+ " -tcl " + TCLScript subprocess.call(Arg) #After executing the tcl script restore back the ‘ALTAIR_HOME’ env os.environ["ALTAIR_HOME"] = Altair_Home SAMPLE SCRIPT: import subprocess,os Altair_Home = os.environ["ALTAIR_HOME"] os.environ["ALTAIR_HOME"]='' TCLScript = ""C:/Users/Documents/HyperMesh_Scripts/HM_Script.tcl" hmBatchLoc = "C:/Program Files/Altair/HM_2021.2/hwdesktop/hm/bin/win64/hmbatch.exe" Arg= hmBatchLoc+ " -tcl " + TCLScript subprocess.call(Arg) os.environ["ALTAIR_HOME"] = Altair_Home 2. Using the following batch script Use 'setlocal' and 'endlocal' batch commands as below to avoid this conflict. BATCH SCRIPT: REM To get the script file to be executed in SimLab set script_name=D:\\Script\\simlab.py REM To get the SimLab.bat location set simlab_bat=D:\\Altair\\SimLab_2022.1\\SimLab.bat REM To get the ALTAIR_HOME path and launch HyperMesh set ALTAIR_HOME=D:\\Altair\\Hw_2021 set hmbatch=%ALTAIR_HOME%\\hwdesktop\\hm\\bin\\win64\\hmbatch.exe REM To localize the changes made to the variable 'ALTAIR_HOME' setlocal REM Launching SimLab.bat and executing the python script. call %simlab_bat% -auto %script_name% -nographics REM To revert back the changes made to the variable. endlocal REM Launching HyperMesh and executing the tcl script. start %hmbatch% -nocommand -h -tcl %script_path%\HM_Script.tcl