HELP: GPSMap60Cx freezing on roundabouts

For the past few months, my GPSMap60Cx has started locking up when
going through roundabouts, which is very frustrating as the only way
to switch it off is by removing a battery. Having to do this
constantly, especially when I'm driving through a series of
roundabouts is driving me crazy, as well as being dangerous.

The weird thing is that it doesn't happen with all roundabouts, and
then sometimes depends on the approach to the offending ones.

I have the latest (I think) unit firmware, v. 4.00.

The unit has clocked up nearly 480.000kms. so maybe old age is setting
in?

Any suggestions gratefully received.

TIA.

Richard.

Previous software updates claimed to fix various shutdown problems,
e.g., Version 3.50, "Fix potential shutdown when propagating in a cul-
de-sac across a map boundary."

http://www.gpsinformation.org/allory/garfeat3.htm#gpsmap60cx


This 4.5 year old post reports a problem when flying in circles (post
#4 by Neo Geo):

http://forums.groundspeak.com/GC/index.php?showtopic=157147

Latest SW versions:

https://buy.garmin.com/shop/store/downloadsUpdates.jsp?product=010-00421-00


Maybe you've found a new "feature". Assuming you're in the UK
(because roundabouts are usually called "traffic circles" in the few
USA states that have them):

http://www.garmin.com/uk/contact-product-support/