Outlook Can't delete files from the trash folder

I need help. I deleted Microsoft office from my Mac Pro with OS X update my Outlook was unstable. I followed Microsoft's guide but I keep getting this message:

The operation can’t be completed because the item “com.microsoft.outlook.officereminders.690AA769-6593-5548-9472-0B831834E504.pli st” is in use.

Please help,

Marlene