I asked about the two cases where a file is in one location but not the other. What will Syncdocs do in each case?
I can give a general answer to this one in the meantime. If the file is in one location it will be downloaded or uploaded to the other location. The exception to this if you are dealing with Office documents or Google Docs/Sheet/Presentation/Forms. Then Syncdocs will attempt to convert the file between formats.
If the file is in one location but not the other, because it has been deleted, and Syncdocs was not running at the time to detect the delete:
1. If the file was deleted from Google, Google knows about the delete and will tell Syncdocs to delete it locally.
2. If Syncdocs was not running and the file was deleted locally, it does not know about this and will re-download the file.
If Syncdocs was running and the file was deleted locally, it does know about this and will delete the file on Google.
EDIT: Generally the same applies for renames as for deletions.
On all Windows, except XP and Server 2003, Syncdocs can also only detect changes made on files it has permissions to see. So if you run Syncdocs from a user account and rename a file as an Administrator, Syncdocs will not have permissions to see this change and will see the rename as a new file, upload it to Google, and download the originally named file from Google.