Every service that is started in a user account context requires a desktop, which requires a USER heap, which requires a contiguous linear address space.
The default USER heap requires approximately 3MB of memory.
The maximum USER linear heap space is 48MB.
The number of services that can be started in a user account context is therefore 48MB/3MB, which is 16.
You can set the non-inactive desktop heap size to 512KB, allowing approximately 96 services to be configured to run in a user account context.
See tip 0052. Change SharedSection=1024,3072 to SharedSection=1024,3072,512.
NOTE: You must restart your computer for the change to become effective.