ViceVersa treats Outlook Files (.PST) as any other file.
When synchronization is activated, ViceVersa overwrites the older PST file with the newer PST file, based on the files' timestamps.
If changes have occurred in both PST files since the last synchronization (e.g. you have worked on both computers where Outlook is used, without synchronizing first), then a conflict is reported.
The conflict pair needs to be resolved manually, i.e. you need to decide which file to keep.
Please note: ViceVersa does not synchronize individual Outlook e-mails, contacts, appointments.