hi, as per the title - my old Nuvi 42 has started doing odd things all of a sudden.
it stopped being able to plan routes to known good postcodes - even old ones that have been there many years.
I have tried updating maps and software via the Garmin Express program and PC - but no change.
otherwise, it seems to start and run normally - ie if it finds/likes an address.
I tried replacing all the visible files on the internal drive with those from a recent backup - in case one of those was corrupt - but this did not help - still does exactly the same thing.
I suspect there may be other files hidden inside the internal memory somewhere that may be corrupt

I read some of the stickies - but most were quite involved and probably trying to fix deeper issues

could anyone direct me to the basics of where to start to troubleshoot this type of problem

much appreciated!