I've tried reinstalled Maya, but it didn't work out well. And the Maya log came out like this... "file -f -new; // Warning: file: C:/Program Files/Autodesk/Maya2018/scripts/startup/rememberViewportSettings.mel line 29: Active stereo does not work with Aero enabled. Active stereo has been disabled. // // untitled // commandPort -securityWarning -name commandportDefault; onSetCurrentLayout "Maya Classic"; [Error 123] The filename, directory name, or volume label syntax is incorrect: 'C:/Users/wcjha/OneDrive/??' // Warning: file: C:\Users\wcjha\Documents\maya\2018\prefs\filePathEditorRegistryPrefs.mel line 4: filePathEditor: Attribute 'aiImage.filename' is invalid or is not designated 'usedAsFilename'. // // Warning: file: C:\Users\wcjha\Documents\maya\2018\prefs\filePathEditorRegistryPrefs.mel line 5: filePathEditor: Attribute 'aiPhotometricLight.aiFilename' is invalid or is not designated 'usedAsFilename'. // // Warning: file: C:\Users\wcjha\Documents\maya\2018\prefs\filePathEditorRegistryPrefs.mel line 6: filePathEditor: Attribute 'aiStandIn.dso' is invalid or is not designated 'usedAsFilename'. // // Warning: file: C:\Users\wcjha\Documents\maya\2018\prefs\filePathEditorRegistryPrefs.mel line 7: filePathEditor: Attribute 'aiVolume.filename' is invalid or is not designated 'usedAsFilename'. // // AbcExport v1.0 using Alembic 1.5.8 (built Jul 13 2016 18:28:45) // AbcImport v1.0 using Alembic 1.5.8 (built Jul 13 2016 18:28:45) # Error: file: C:/Program Files/Autodesk/Maya2018/plug-ins/MASH/scripts/MASHCreateUI.mel line 148: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # updateRendererUI; // Warning: file: C:/Program Files/Autodesk/Maya2018/scripts/others/supportRenderers.mel line 64: The renderer "arnold" used by this scene, is not currently available. The "mayaSoftware" renderer will be used instead. // evalDeferred "shaderBallRendererMenuUpdate"; // Warning: line 1: filePathEditor: Attribute 'aiStandIn.dso' and label 'Standin' have been saved already. // // Warning: line 1: filePathEditor: Attribute 'aiVolume.filename' and label 'VDB' have been saved already. // // Warning: line 1: filePathEditor: Attribute 'aiImage.filename' and label 'Image' have been saved already. // // Warning: line 1: filePathEditor: Attribute 'aiPhotometricLight.aiFilename' and label 'IES' have been saved already. // # Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # # Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # # Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # # Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # import arnold // Successfully imported python module 'arnold' import mtoa // Successfully imported python module 'mtoa' import mtoa.cmds.registerArnoldRenderer;mtoa.cmds.registerArnoldRenderer.registerArnoldRenderer() # Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: IOError: file C:\Program Files\Autodesk\Maya2018\bin\python27.zip\logging\__init__.py line 935: 22 # // Error: Failed to register renderer 'arnold' // evalDeferred "shaderBallRendererMenuUpdate"; // Error: file: C:/Program Files/Autodesk/Maya2018/scripts/others/pluginWin.mel line 290: initializePlugin function failed (mtoa) // "
https://arnoldsupport.com/2016/10/08/mtoa-the-curse-of-pymel-log/