Windows 7 Previous Version empty in File Properties dialog

It seems like you were trying to configure System Protection and the Previous Versions feature on your Windows system. The steps you followed are correct for setting up System Protection to create restore points, which allow you to restore previous versions of files. However, you mentioned that the Previous Versions tab was empty, indicating that the restore points might have been deleted.
Here's a summary of the steps you performed:
1. Accessed the Control Panel and selected System.
2. Selected System Protection.
3. Chose the D drive in the Protection Settings section.
4. Clicked on the Configure button.
5. Enabled "Only restore previous versions of files."
6. Set the Max Usage to 50%.
7. Clicked on the OK button.
8. Clicked on the OK button again.
9. Closed the System dialog.
Given that the previous versions were not available for a file that was modified multiple times, it's likely that the restore points were deleted or not properly configured. When you created a new Restore Point, the functionality started working correctly again.
To ensure that this doesn't happen in the future, make sure to periodically check the System Protection settings to confirm that the restore points are being created and not deleted unexpectedly. It's also a good practice to manually create restore points before performing critical system changes.