Hi Jennifer,
The issue that you’ve encountered regarding the time format on your Windows 10 computer may be caused by some configuration or files mismatched. To sort out your concern, we suggest that you manage the settings for Region from the Control Panel. This is to properly set up the configuration for the 12-hour format and verify if the issue is not related to the settings. To do this, you may follow the steps below:
- Click Start, type Control Panel and press Enter.
- On the Control Panel search box, type Region and select it from the search results.
- Select the Format tab, under the Language preferences section, change the Short time option to h: mm tt by clicking the drop-down menu.
- Click Apply > OK to save the changes.
- Once you’re done, you may check if you're able to set the time on your PC to the 12-hour format.
Keep us updated about your concern for additional assistance.