Here's how to sort data case-sensitively in Excel:

1. Select the data range you want to sort.
2. Go to the "Data" tab on the Excel ribbon.
3. Click on "Sort" in the "Data Tools" group.
4. In the "Sort Warning" window (may appear depending on your Excel version), choose "Expand the selection" if you want to include the header row in the sorting. Otherwise, click "OK" to continue.
5. In the "Sort" window, click the arrow next to the "Sort by" dropdown menu and choose the column you want to sort by.
6. Click the "Sort On" dropdown menu and choose "Values."
7. Enable Case Sensitivity: This is the key step. Check the box next to "Case sensitive" to ensure uppercase and lowercase letters are treated differently during sorting.
8. Choose "Ascending" or "Descending" depending on how you want the data sorted (A-Z or Z-A).
9. Click "OK" to sort your data case-sensitively.

By following these steps, your data will be sorted with uppercase letters appearing before lowercase letters in the chosen column.