diff -Nru os-prober-1.70ubuntu2/debian/changelog os-prober-1.70ubuntu3/debian/changelog
--- os-prober-1.70ubuntu2/debian/changelog	2016-02-23 17:11:18.000000000 +0100
+++ os-prober-1.70ubuntu3/debian/changelog	2016-03-08 09:37:28.000000000 +0100
@@ -1,3 +1,10 @@
+os-prober (1.70ubuntu3) xenial; urgency=low
+
+  * Check for MSDOS extended partitions and skip any further tests which
+    would require the partition to be mounted (LP: #1374759). 
+
+ -- Stefan Bader <stefan.bader@canonical.com>  Tue, 08 Mar 2016 09:35:20 +0100
+
 os-prober (1.70ubuntu2) xenial; urgency=medium
 
   [ Mario Chamorro ]
diff -Nru os-prober-1.70ubuntu2/os-prober os-prober-1.70ubuntu3/os-prober
--- os-prober-1.70ubuntu2/os-prober	2015-09-29 05:02:53.000000000 +0200
+++ os-prober-1.70ubuntu3/os-prober	2016-03-08 09:35:15.000000000 +0100
@@ -132,6 +132,12 @@
 		continue
 	fi
 
+	# Skip MSDOS extended partitions (container)
+	if is_dos_extended_partition $partition; then
+		debug "$partition: DOS extended partition; skipping"
+		continue
+	fi
+
 	# Skip partitions used in software RAID arrays
 	if grep -q "^$mapped" "$OS_PROBER_TMP/raided-map" ; then
 		debug "$partition: part of software raid array"