Must be......
I've been getting this for quite a while on load up...........
phpBB : Critical Error
Error doing DB query userdata row fetch
DEBUG MODE
SQL Error : 1016 Can't open file: 'phpbb_sessions.MYI' (errno: 145)
SELECT u.*, s.* FROM phpbb_sessions s, phpbb_users u WHERE s.session_id = '64f405283192d702c220fcffa24c4dba' AND u.user_id = s.session_user_id
Line : 341
File : sessions.php