I did the following: 1) Select the entire sheet by clicking on the extreme top left header (having a little triangle in it). 2) Right click --> Format cells --> Un-check the locked cells under the protection tab. 3) Convert your data to data table. 4) Select the column you want to lock. 5) Right click --> Format cells --> Check the locked cells under the protection tab. 6) Goto the Review tab and click on the protect sheet, put a password.