Is it okay to rename the MySQL data files (FRM) manually? Recently I realized the case sensitivity issues in MySQL. I wanted to convert my upper case table names to lower case using this solution but I forgot to do Step 1, and completed the remaining steps. Now I couldn't access my tables that are in upper case. Renaming the tables using 

mysql&gt;  rename table BOOK to book;
ERROR 1017 (HY000): Can't find file: './las_data_3_dt2014/book.frm' (errno: 2)


returns error.

I'm unable to use mysqldump on my database.

mysqldump: Got error: 1146: Table 'las_data_3_dt2014.adjustment_type' doesn't exist when using LOCK TABLES 


I want to know if it's okay to rename the upper case .FRM files to corresponding lower case files, so that I can run the rename commands and access the data again.
change lower_case_table_names back again

Then you should be able to access your tables. 

But yes, as long as they as MyISAM tables you CAN rename them. Best to do it while mysql is shutdown. Need to change the MYD and MYI files too.