I just received my Freestyle Libre this week, so I'm not sure I can be of help to the OP original question. However, I have had some issues with my first attempt at using this Abbott product.
When I inserted the first sensor and attempted to start it, the reader came back with the message: Sensor ended. Also, the Freestyle reader itself will not hold a charge and must be plugged in before it will turn on.
This product is new to Canada (available in October, although, I see it's been in use in other regions much longer) - so I assume Abbott is still having some technical difficulties getting the Freestyle reader and sensors to work correctly.
What bothers me the most though is the poor customer support that Abbott provided. In order to troubleshoot the problem, I phoned the number on the Abbott web site, waited on hold for a significant time, and was told by the agent that the 1-888 number on the Web site was for registration and sales only. Technical or warranty issues had to be placed with a different number which wasn't listed on the Web site. So they gave me the correct number and my wait to speak to Technical Support began.
On the first call, I waited 4 hours on hold and finally had to hang up. I tried again that afternoon and waited another 3 hours on hold before an Abbott agent finally answered the phone. We scrolled through the error log on the Freestyle reader and determined that the Abbott reader and Sensor were indeed failing and needed replacement. They'll be sending me the new items by the end of next week.
So, my initial Freestyle experience has been a 100% failure of the product along with somewhat non-responsive technical support. On the plus side, there was no argument that reader and sensor were both defective and they would pay for replacement.
Having said all that, the promise of a easier method of testing is still compelling. I use a Medtronic pump, so the Freestyle won't provide the same CGMS that the Medtronic system would, however, given it lasts a full two weeks it definitely has benefits over the finger poking method - I do about about 6 tests a day which can be difficult at work etc. (I'm using the Bayer Contour for this).
So, I'm looking forward to getting a new reader and sensor from Abbott and giving this another try.