how many data files can be stored in access before it crashes
None. Access doesn't store "data files".
The capacity of an Access database (A2000 and later) is 2 GByte, including all
tables, forms, reports and other objects. There is no explicit limit on the
number of records in a table; I'm aware of production databases with tables
exceeding 20,000,000 records.
John W. Vinson [MVP]