This will show what version of mtoa Maya is trying to load.

Check the error in the Script Editor (Windows > General Editors > Script Editor).

Maya is attempting to load the wrong version of MtoA.

NOTE: Maya has to be restarted to activate the changes made to the Maya.env file How to get Maya Environment Variable in the Script Editor.

Follow this tutorial to apply Environment Variables in the Script Editor:.

To check Maya's environment, open the Script Editor and enter the following MEL command:.

Or is pointing to an old version of MtoA.

MtoA location is missing from Maya's PATH environment.

Locate the mtoa.mll plug-in and check the box next to 'Loaded'.

Navigate to Windows > Settings/Preferences > Plug-in Manager.

After the fresh install completes, open Maya and load MtoA through the Plug-in Manager:.

Previous versions of MtoA are also available here: Solid Angle Arnold Archive.

Close Maya, and follow this guide to locate and install the latest version of Arnold: Where to download Arnold Updates.

To reinstall/update to the latest version, follow these steps:.

Arnold is ai.dll on Windows, libai.so on Linux, or libai.dylib on OSX.

Sometimes, DLLs are missing from the MtoA bin folder, or the plug-in entirely was missing

If MtoA loaded previously, but currently does not, which indicates that the installation was incomplete or corrupted.

Here is a screencast on How to Use Core info to check the SSE compatibility.

As of Arnold 4.2.16.2, the SSE requirement is now SSE 4.1.

To address the causes, follow these steps:

Unable to find module info file