If the Megascans button is not visible on the Editor Shelf even after successfully installing the plugin, then it could be due to a missing library in your Editor. This library is PYMEL for the Python 3 interpreter of your Maya 2022/Maya 2023 Editor.

Probable Cause of the Missing Library

Starting with Maya 2022, Autodesk is transitioning Python support from py2 to py3.

Maya 2022 comes compatible with both py2 and py3 python interpreters. However, it initiates with py3 python-mode by default.

Both the Python interpreters have a library called PYMEL which is required for the installation of the MS Plugin in the Maya Editor.

The installation of this library varies depending on the python version:

• py2 always gets installed (by default) with your Maya 2022 Editor installation.
• py3 only gets installed when you select the component ("PYMEL for PYTHON3") during the installation process of Maya 2022-2023 Editor (as shown in the image below).

It's possible that you did not enable the PYMEL for Python 3 checkbox on the installation wizard.

You can confirm that PYMEL is missing from your editor by following these steps:

• Go to the Start menu on your PC, and type CMD in the search box to locate the Command Prompt app.
• Right-click on the app and select "Run-As-Administrator" (as indicated by the yellow arrow below).

💡 Important Note: Starting the Command Prompt with Admin rights is very important here. Otherwise, you will not be able to perform the following steps in the process.

• Once the Command Prompt opens notice that a directory will already be open (as shown below, it’s C: in our case).

• Now, from within the Command Prompt, go to the (root i.e. bin) installation directory of your Maya 2022-2023 Editor i.e. <Your Maya installation directory>\bin\>. If the installation directory is in the same drive as the one already open in the Command Prompt, use the command cd <path-to-your-Maya-installation-directory> (as shown below).

Insert the path as per your directories.

If the installation directory is in a different drive from the one already open, then use the following commands (as shown below).

• To change drive, type: D:
• To go to the directory within the drive, type: cd <path-to-the-root-directory>

Insert the path as per your directories.

• Once in the root (bin) directory, type the following command (as shown in the red highlight below) to check if the PYMEL library (for Py3) is installed or not.

  mayapy -m pip list

If installed, the PYMEL library will be listed in the results (as highlighted below).

If it’s not installed, the PYMEL entry (as indicated by the yellow highlight below) will NOT show in the results. And that is what's causing the issue.

Solution

Install the PYMEL library by following these steps:

• Close the Maya Editor if running.
• Head back to the Command Prompt or reopen it as an admin if it was closed.

💡 Important Note: It is very important that you run the Command Prompt with Admin rights, otherwise you won’t be able to install the PYMEL library.

• Make sure that you are in the(root i.e. bin) installation directory of your Maya 2022-2023 Editor (as shown in the yellow highlight below).

The path will be as per your directories.

• Once in the root (bin) directory, type the following command (as shown in the red highlight below) and press Enter:

  mayapy -m pip install "pymel>=1.2.,<1.3."

This will download and install the latest version of the PYMEL library on your machine (as shown in the red highlight below).

• Once successfully installed, type the following command (as shown in the yellow highlight below) to confirm that the PYMEL library (for Py3) was installed:

  mayapy -m pip list

Now, you should see the PYMEL entry in the results (as indicated by the yellow arrow below).

• Next, reinstall the MS plugin (in case, you had uninstalled it) and start your Maya 2022 Editor. The MS Plugin should appear in your Editor shelf now.

💡 Important Note: Make sure to select "Allow" for the 2 prompts that might appear upon startup regarding the MS Plugin.