Interface unresponsive asking for root password

[Papoteur]

I installed and configured deja-dup for daily backup on an external drive in encrypted partition.
At boot, this partition is not mounted, and sometime not connected.
When I connect the drive, deja-dup starts and ask for the root password. But I can't give it, the dialog box is unresponsive. I have to kill it.
OS : Mageia
deja-dup-32.0-1.1.mga5
duplicity-0.6.25-2.mga5
Settings:
org.gnome.DejaDup last-restore ''
org.gnome.DejaDup periodic true
org.gnome.DejaDup full-backup-period 90
org.gnome.DejaDup backend 'file'
org.gnome.DejaDup last-run '2016-07-29T06:41:01.657550Z'
org.gnome.DejaDup nag-check '2016-07-18T05:47:37.200934Z'
org.gnome.DejaDup prompt-check '2016-01-16T06:43:14.928333Z'
org.gnome.DejaDup root-prompt true
org.gnome.DejaDup include-list ['/home/yves/pro', '/home/yves/html']
org.gnome.DejaDup exclude-list ['$TRASH', '$DOWNLOAD']
org.gnome.DejaDup last-backup '2016-07-29T06:41:01.657550Z'
org.gnome.DejaDup periodic-period 1
org.gnome.DejaDup delete-after 0
org.gnome.DejaDup.S3 id ''
org.gnome.DejaDup.S3 bucket ''
org.gnome.DejaDup.S3 folder 'Netbook-M4'
org.gnome.DejaDup.GDrive email ''
org.gnome.DejaDup.GDrive folder '/deja-dup/Netbook-M4'
org.gnome.DejaDup.Rackspace username ''
org.gnome.DejaDup.Rackspace container 'Netbook-M4'
org.gnome.DejaDup.File path ''
org.gnome.DejaDup.File short-name 'Volume de 789 GB'
org.gnome.DejaDup.File uuid 'a070ee60-9570-449a-836b-a0234aa99244'
org.gnome.DejaDup.File icon '. GEmblemedIcon .%20GThemedIcon%20drive-harddisk-usb%20drive-harddisk%20drive .%20GEmblem%20changes-allow%201'
org.gnome.DejaDup.File relpath b'dup'
org.gnome.DejaDup.File name 'HGST HTS541010A7E630: Volume de 789 GB'
org.gnome.DejaDup.File type 'volume'

[Michael Terry (mterry)]

We no longer prompt for a root password