Sorry for taking so long to reply. We have heard similar reports, but unfortunately it is very hard for us to duplicate or trouble shoot due to all the combinations.We really appreciate other user's help!
When opening and editing a file via DriveHQ FileManager (Desktop Express), if you save the file, DriveHQ FileManager monitors the file change, and automatically saves the file back to the server. If you have some anti-virus / security software blocking it from monitoring file changes, then it will not work.
You might want to explicitly set a Synchronized Folder. I guess automatic folder synchronization will also be disabled in your case. But you can manually start the synchronization.