Q100041: Mari launch issues

• Directory permission for config files.
• Intel HD Graphics Card (not supported).
• Computer with two graphics cards using the wrong one.
• A 10th or 11th generation Intel CPU.
• The PYTHONHOME environment variable has been set to a different Python version or an invalid directory.
• Issues with components of Mari that are reused when Mari is reinstalled.

Directory permission for config files

Navigate to your Mari config folder and recursively change the permissions of the TheFoundry folder. The method of changing permissions can vary between OS.

• On Windows it is easier to use the File Explorer to select the .mari folder in your home directory, and grant full permissions to your user account, making sure to include all subfolders and files.
• On Linux and Mac systems this is done best through the chmod command.

Intel HD Graphics Card

Intel HD graphics are not supported by Mari. You will require an NVIDIA or AMD graphics card with the latest drivers. More details for system requirements can be found here. 

Computer with two graphics cards

If your computer has two GPUs, it may be using an unsupported Intel HD graphics card to launch Mari. To resolve this issue, please refer to the following article:
Q100040: Assigning your Nvidia GPU to Mari on Windows to prevent launch issues

10th or 11th generation Intel CPU

There is currently a known issue with Mari and 10/11th generation Intel processors, which can cause crashes during launch or when loading projects. This can be prevented by setting the following environment variable:

OPENSSL_ia32cap=~0x200000200000000

Further information on this known issue and full instructions for applying the workaround can be found in the article linked below:

Q100573: Katana, Mari, and Nuke can fail to launch with a 10th or 11th Generation Intel CPU 

PYTHONHOME Environment Variable

Mari 5 upgraded from Python 2.7 to Python 3.7. Older pipelines are built around the use of Python 2.7 and may be using the PYTHONHOME environment variable to point to a specific Python install. If this environment variable is pointing to an invalid directory or an out-of-date version of Python, it might cause a crash or disable some features. Unsetting the environment variable before the launch of Mari will solve those issues as Mari will use its own Python install.

Note: Please review the following article for how to unset environment variables on your machine:
Q100127: How to delete/unset environment variables

Safer Mode and leftover Mari components from a previous install.

If you've tried all the above, you tried reinstalling Mari, and the problem persists, it may be that your reinstall isn't a fresh version of Mari. This is because when the software is uninstalled, some components may not be removed. So if the problem is with one of these components, and Mari reuses them when it gets reinstalled, the issue will persist. This is particularly relevant for the config files. For a complete uninstall of Mari, please follow the steps in the following article:
Q100138: Uninstalling MARI

Before uninstalling Mari, safer mode can also be attempted, as it will replicate a fresh install of Mari. This should confirm whether uninstalling Mari or removing one of its additional components might resolve your issue. To launch Mari in safer mode, please refer to the following article:
Q100022: Using safer mode to launch Mari as a fresh install

FURTHER HELP