nautilus 'freezes' when using "copy to ..." option more than once

But only when using the copy to... option on files from another partition, locally there is no issue.
The nauutilus window just goes gray & no other nautilus windows can be opened or accessed if already open.
The nautilus process is still running, no crash.

Test case here:
Open nautilus > Other location+ > browse to a file in another partition > r. click > copy to > pick a local folder. Copy is successful.
Repeat on another file, nautilus 'freezes', no copy happens, nautilus is unresponsive but not crashed. Only killing nautilus will bring back, trying to quit nautilus in terminal does not work, shows this -
$ nautilus -q

(nautilus:5934): GLib-GIO-CRITICAL **: g_dbus_interface_skeleton_unexport: assertion 'interface_->priv->connections != NULL' failed

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: nautilus 1:3.18.4-0ubuntu1
ProcVersionSignature: Ubuntu 4.3.0-5.16-generic 4.3.3
Uname: Linux 4.3.0-5-generic x86_64
ApportVersion: 2.19.3-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Jan 7 18:59:45 2016
GsettingsChanges:
 b'org.gnome.nautilus.window-state' b'geometry' b"'1455x782+465+298'"
 b'org.gnome.nautilus.list-view' b'default-column-order' b"['name', 'size', 'type', 'owner', 'group', 'permissions', 'mime_type', 'where', 'date_modified', 'date_accessed', 'date_modified_with_time']"
InstallationDate: Installed on 2016-01-07 (0 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160107)
SourcePackage: nautilus
UpgradeStatus: No upgrade log present (probably fresh install)