If a database is served and you wish to use any non-Progress backup tools, a PROQUIET must be used to force a sync of memory down to disk. This will suspend writes during the period the quiet point is enabled but will allow an OS tool to safely backup the files on disk and make sure all files are up to date. Once copied, the quiet point can be released. PROQUIET is only a feature of Enterprise Database License.
Otherwise, the database needs to first be shutdown before the non-Progress backup is taken.
For further information refer to Article
Can Third Party tools be used to perform online or offline backups ?
If the database is in single user mode, do not attempt to use a non-Progress backup to copy the files on disk as they are dynamically being updated and the non-Progress tool will most likely catch the files midstream and the resultant files will most likely be out of sync.
