excel file read-only but not locked I open an Excel file (Excel 2008) and it opens as read-only.  File info shows that it is not locked and my user account has Read-Write access and it's a LOCAL file.

Please advise on how to get back to editable file?

File name is ca.xls  so all those posts discussing / are not relevant.
Redo permissions and ACL's in Recovery.
Boot to Recovery. 
Open Terminal from the Utilities menu. 
Type in 'resetpassword' press return. 
Select your drive and user account. 
Hit button to reset ACL's. 
Reboot. 
Attempt to manipulate your file.