Hi. We're sorry to hear of your experience with your HD70. Under normal conditions should be a very easy, accurate and versatile scanner to use. There are enough variables in wall construction (insulation properties, moisture issues, general inconsistencies, etc. etc.) that we would have had to do some trouble shooting with you to figure it out. I’m positive we can help you out, for as we know from experience, there is always a reason and a solution for these problems. Please contact us. We offer toll free support by phone (800 245 9265) during normal business hours Mon. thru Fri. 8:00am to 5:00pm PST. We also maintain a 24/7 interactive online knowledge base and email support that can we found on the Zircon website. Thank you.