MySQL Error - Can't open file: 'something.MYD'. (errno: 145)

The following error may occur with a MySQL database table:

Can't open file: 'TableName.MYD'. (errno: 145)

This error usually means that 'TableName' table has become corrupt. From my experience, it appears that the error commonly affects a table used for storing sessions and may occur when the database has used up all allocated disk space. Additional disk space will normally need to be allocated.

Also, run the following SQL query via phpMyAdmin:
REPAIR TABLE TableName 

Remember to change TableName with the name of the corrupted table as shown in error message respectively.