The desktop application notifies the user about every change applied to files and folders inside the user's shares.
On the setting page of the PC application, you have the option of disabling these notifications.
Simply open up the desktop client, click on "Settings", then mark the checkbox next to "Disable file messages". Finally, click on "Update" to apply your changes.
This option only makes it so that no popup notifications will be shown when a file has been changed by other users.
A pop-up will still be shown when:
-You synchronize files.
-There's conflict between files.