Running the community edition, I've begun getting:
ERROR 122 (HY000): CAL0007: Update failed on XXX table. opening a column file. The file was not found or was inaccessible.
when I try to do straightforward updates to various tables, i.e.
update XXX set x = 'aaa' where x = 'bob';
I can query each of the tables just fine, but can't update.
(addenda): if I leave a session after getting the above message, then when I start a new session and try to do an update I get:
ERROR 122 (HY000): IDB-2010: Unable to perform DDL/DML because session [prior #] is currently updating XXX