In Windows Explorer, you can select the first file in a group, press and hold the left SHIFT key, and then select the last file in the group. If you do this with the right SHIFT key, you may have to click twice to select the files?
To workaround this behavior:
1. Control Panel / Accessibility Options.
2. Select the Keyboard tab.
3. Press the Settings button under FilterKeys.
4. Clear the Use shortcut box under Keyboard shortcut.
5. Press OK.
6. Press Apply and OK.