The built-in InnoDB in MySQL can only open tables that were created in REDUNDANT or COMPACT format. Starting with MySQL version 5.0.21, an attempt to open a table in some other format results in ERROR 1146 (42S02): Table 'test.t' doesn't exist. Furthermore, a message “unknown table type” appears in the error log.

In the InnoDB Plugin, you may rebuild an incompatible table by issuing a statement ALTER TABLE table_name ROW_FORMAT=COMPACT.