Upload Center is a tool that is included in Microsoft Office. When you install Office 2010/2013/2016 versions, the Microsoft Office Upload Center installs automatically.
Microsoft Office Upload Center
The Upload Center gives you a way to see the state of files you’re uploading to a server, in one location. When you upload a file to a web server, Microsoft first saves that file locally to the Office Document Cache before it starts the upload, which means that you can save changes and immediately continue working even when you are offline or have a bad network connection.
Microsoft Office Upload Center uses a feature known as Efficient File Transfer (EFT) to help reduce bandwidth usage between SharePoint and Office applications.
After installing Office, you may see a small circular yellow icon in your Windows taskbar notification area.
This is the Microsoft Office Upload Center icon. Clicking on it will open the Upload Center. Right-clicking on it gives you other options.
Alternatively, you can also access it via Start Menu > Microsoft Office > Microsoft Office 2010/2013/2016 > Tools > Microsoft Office 2010 Upload Center.
When you open it, you will see the list of all files that have been cached. You can monitor here, the status of files that are in the process of being uploaded.
Remove Office Upload Center icon
You can, if you wish, disable or remove the Microsoft Office Upload Center icon from displaying in the notification area of your Taskbar.
You can do so by unchecking Display icon in notification area check-box in the Display Options in Settings.
Disable Office Upload Center
If you wish to completely disable Office Upload Center, then create a system restore point first and then open the Registry Editor. Navigate to the following registry key:
Delete the OfficeSyncProcess key.
You can read more about it at Microsoft.