The Zimbra ZDB takes up too much disk space on the C hard drive

You can change the path of the Zimbra ZDB -file (Outlook file which keeps the mail and infomartion on the loca hard drive) to e.g. the D-partition (if exists) By default it's located at C:\Users\username\AppData\Local\Microsoft\Outlook

Open Outlook and go to File -> Account settings -> Data Files -> Choose YOUR Zimbra account (Double-Klick) -> ZDB Configuration -> Check "Store ZDB in the external folder" and choose the path to the new folder.

Klick on "Move ZDB" -> OK -> The file will be MOVED there. This may take some time.