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You don't need to know the details right now, but it's based on data in column D. Meaning we don't want any changes in the following columns. We wanna make sure that's empty looking right now. Sometimes, by the way, you'll see that this box is checked, or blank as it is now, sometimes it'll be black, meaning some are locked, some are not. So let's begin by clicking the upper left corner, that selects the entire worksheet, let's right-click format cells, go to protection, unlock. Because let's say we've got a situation where we want others to be able to make some editing changes to clean up this file, but we wanna be careful about not letting them make changes in certain areas. So probably all the cells in this worksheet, as in most worksheets, it's locked. Locking cells has no effect until you protect the worksheet. If you right-click any cell, in Excel, and go to format cells, if you go to the protection tab, and by the way it's not always selected but, we see here the cell is locked. And it might begin with something that doesn't seem related at first. Gives us control in a lot of different ways. Now, protecting a worksheet probably is the command that you're more likely to want to use. But of course, I do right now, and some point I will un-protect the workbook. If I click protect workbook right now, well if I don't know the password, I can't change that status.
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So while it's in this state, can't do this. And even if I were curious and thought, I wonder if there's a hidden sheet? I don't even know that necessarily, because I can't get to those commands.
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Notice how many of the commands are grayed out. Right now I'm about to right-click on the current sheet tab. I know it, I might tell certain others, not others, and if I save the workbook it stays in this state. Protect workbook, need to provide a password. If we protect a workbook, you cannot insert a new sheet, move a sheet, delete a sheet, and as we'll see in a moment, practically all commands available as we right-click a tab are going to be inhibited. And this is primarily about the structure of a workbook. Both of the commands that I mentioned are on the review tab in the ribbon. Let's first talk about protecting a workbook. We're looking at the file 11-Protection, and the very first sheet is called Worksheet Protection. One for protecting the workbook, one for protecting the worksheet. If you wanna provide better security for your data, and possibly if you've got multiple users using the same workbook, you wanna be aware of two commands.