Accessing nested dictionary values. Plistlib, Python 2.7

[nilamo]

for item2 in item['_items']:
    HDsize = item2['size']

Sounds like things that aren't hard drives, don't have a size.  So, check if size exists before getting it:

for item2 in item["_items"]:
    if "size" in item2:
        HDsize = item2["size"]
        # etc