OmniPlan is pretty good at working with Microsoft Project documents, and we're always working to make it even better, but there are a few things you should watch out for. Assignments to task groups — In Microsoft Project, a resource can be assigned to a group of tasks. In OmniPlan, this just assigns the resource to all tasks in the group, not to the group itself. When you import a Microsoft Project document with an assignment to a task group, a warning appears in the violations column to let you know that the assignment was not imported.
Efficiency — Microsoft Project doesn't support the OmniPlan efficiency attribute for resources.
Unequal assignments — In Microsoft Project, if you assign more than one resource to a task you can specify how many hours of effort each assigned resource should contribute. If you don't specify, it assigns however much work to each that will complete the task earliest (taking schedule and resource assigned units into account). OmniPlan always uses that same automatic method. So, a task with effort hours specified for its resources may take a different amount of time in OmniPlan than it did in Microsoft Project.
Unicode characters — The Microsoft Project MPX format doesn't support the Unicode character encoding standard. If your project contains Unicode characters (say, some Chinese text for instance), you should use the more modern Microsoft Project XML or MPP format instead.