diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
index 8a254a5b6a..f2457b1dde 100755
--- a/scripts/analyze-migration.py
+++ b/scripts/analyze-migration.py
@@ -429,6 +429,9 @@ def __init__(self, desc, file):
         super(VMSDFieldStruct, self).__init__(desc, file)
         self.data = collections.OrderedDict()
 
+        if 'fields' not in self.desc['struct']:
+            raise Exception("No fields in struct. VMSD:\n%s" % self.desc)
+
         # When we see compressed array elements, unfold them here
         new_fields = []
         for field in self.desc['struct']['fields']:
@@ -477,6 +480,10 @@ def read(self):
                     raise Exception("Subsection %s not found at offset %x" % ( subsection['vmsd_name'], self.file.tell()))
                 name = self.file.readstr()
                 version_id = self.file.read32()
+
+                if not subsection:
+                    raise Exception("Empty description for subsection: %s" % name)
+
                 self.data[name] = VMSDSection(self.file, version_id, subsection, (name, 0))
                 self.data[name].read()
 
@@ -574,10 +581,13 @@ def __init__(self, filename):
         }
         self.filename = filename
         self.vmsd_desc = None
+        self.vmsd_json = ""
 
-    def read(self, desc_only = False, dump_memory = False, write_memory = False):
+    def read(self, desc_only = False, dump_memory = False,
+             write_memory = False):
         # Read in the whole file
         file = MigrationFile(self.filename)
+        self.vmsd_json = file.read_migration_debug_json()
 
         # File magic
         data = file.read32()
@@ -635,9 +645,11 @@ def read(self, desc_only = False, dump_memory = False, write_memory = False):
         file.close()
 
     def load_vmsd_json(self, file):
-        vmsd_json = file.read_migration_debug_json()
-        self.vmsd_desc = json.loads(vmsd_json, object_pairs_hook=collections.OrderedDict)
+        self.vmsd_desc = json.loads(self.vmsd_json,
+                                    object_pairs_hook=collections.OrderedDict)
         for device in self.vmsd_desc['devices']:
+            if 'fields' not in device:
+                raise Exception("vmstate for device %s has no fields" % device['name'])
             key = (device['name'], device['instance_id'])
             value = ( VMSDSection, device )
             self.section_classes[key] = value
@@ -666,31 +678,34 @@ def default(self, o):
 
 jsonenc = JSONEncoder(indent=4, separators=(',', ': '))
 
-if args.extract:
-    dump = MigrationDump(args.file)
-
-    dump.read(desc_only = True)
-    print("desc.json")
-    f = open("desc.json", "w")
-    f.truncate()
-    f.write(jsonenc.encode(dump.vmsd_desc))
-    f.close()
-
-    dump.read(write_memory = True)
-    dict = dump.getDict()
-    print("state.json")
-    f = open("state.json", "w")
-    f.truncate()
-    f.write(jsonenc.encode(dict))
-    f.close()
-elif args.dump == "state":
-    dump = MigrationDump(args.file)
-    dump.read(dump_memory = args.memory)
-    dict = dump.getDict()
-    print(jsonenc.encode(dict))
-elif args.dump == "desc":
-    dump = MigrationDump(args.file)
-    dump.read(desc_only = True)
-    print(jsonenc.encode(dump.vmsd_desc))
-else:
+if not any([args.extract, args.dump == "state", args.dump == "desc"]):
     raise Exception("Please specify either -x, -d state or -d desc")
+
+try:
+    dump = MigrationDump(args.file)
+
+    if args.extract:
+        dump.read(desc_only = True)
+
+        print("desc.json")
+        f = open("desc.json", "w")
+        f.truncate()
+        f.write(jsonenc.encode(dump.vmsd_desc))
+        f.close()
+
+        dump.read(write_memory = True)
+        dict = dump.getDict()
+        print("state.json")
+        f = open("state.json", "w")
+        f.truncate()
+        f.write(jsonenc.encode(dict))
+        f.close()
+    elif args.dump == "state":
+        dump.read(dump_memory = args.memory)
+        dict = dump.getDict()
+        print(jsonenc.encode(dict))
+    elif args.dump == "desc":
+        dump.read(desc_only = True)
+        print(jsonenc.encode(dump.vmsd_desc))
+except Exception:
+    raise Exception("Full JSON dump:\n%s", dump.vmsd_json)