Re: My appointment days are duplicated to two days when my other computers sync.

Hi KyleNVA,

The issue could be related to incorrect configuration in OWA (Outlook Web App). To solve the issue, please try the steps below:

In the Pre-Upgrade Office 365:

1. Log into OWA. Click “Options” in the upper right, then select “See All Options…”
2. Click “Settings” in the left panel, then click “Regional”, please make sure that all the devices are using the same time zone.
3. After that, click “Calendar” in the top, select the work week days in your region and save the change.   

In the After-Upgrade Office 365:

1. Log into OWA. Then click the setting icon in the upper right and select “Options” in the drop down menu.
2. Click “settings” in the left panel. then click “Regional”, then check if all the devices are using the same time zone.
3. After that, click “Calendar” in the top, select the work week days in your region and save the change.