The error "MWindow::init_shm: /proc/sys/kernel/shmmax is 0x1000000 It should be at least 0x7ffffff" in Cinelerra typically indicates that the system's maximum shared memory size is too low. Cinelerra uses shared memory to store data that needs to be shared between different processes.
To fix this error, you will need to increase the maximum shared memory size on your system. You can do this by editing the /etc/sysctl.conf file and adding the following line:
kernel.shmmax = 1073741824
This will set the maximum shared memory size to 1 GB (1073741824 bytes). You will need to have root privileges to edit this file.
Once you have made the change, you will need to apply the new configuration by running the following command:
sysctl -p
This will reload the system's kernel parameters from the /etc/sysctl.conf file.
After increasing the maximum shared memory size, you should be able to run Cinelerra without encountering the "MWindow::init_shm" error. If you continue to experience this error, you may need to increase the shared memory size even further.