What is the maximum number of Tasks/Milestones or a combination that can be added to a Project (referring to the entries in the Project Schedule tab)?
Upon checking, there is currently no documented limitation on the number of Project Tasks that can be created on a Project record. However, it is not recommended to have a very large number of tasks within a project as this may cause performance issues on your account such as slowness or error messages. The system may no longer handle such large data, hence it may throw an error message.
“For the optimal performance, keep mainly projects shorter than one year, with less than 1000 tasks. Use sub-projects when possible.”