Files that are simultaneously accessed by multiple people (such as databases or accounting software) or are frequently updated outside of the control of the user (such as email repositories) should not be synced with Cloud services.
Due to the nature of Cloud services and these file types, syncing such files will result in unexpected consequences and potentially data loss.
In the scenario where multiple users are simultaneously accessing the same file, the mechanism that controls which file is the master file will create duplicates to ensure the changes made by the other open editing sessions are not lost. The end result is that, within a short period of time, dozens (potentially hundreds or even thousands) of near-duplicates will be created, each containing the alterations made by the individual users - none of which will contain all of the entries.
In the scenario of files that are updated out of the control of the user, every time a change occurs to a file that is syncing with the ECHOShare service, the file is re-synced with the service. In the case of these automatically updated repositories, due to the frequency of updates and that they are often quite large, they can clog the syncing process causing the ECHOShare Desktop Agent to continuously re-initialise the upload and never complete (because it keeps restarting before it finishes).
The best practice for these file types is to store them on a locally-accessible drive and then use the backup function within ECHOShare if desired, purely as a disaster-recovery option.