I buy and sell and use Tomtom units. One hint to the problem you describe also manifests itself with a display on the GPS Navcore/Map Version screen screen of 32mb ram in a unit with 64mb ram. Another symptom will be if the unit is operated in Home under 'Operate My Device' and you will get only a partial map display...you will get the vehicle icon and colors, but the streets and the rest of the data does not load. You also may get a message like "No useful GPS data found near destination location" if you plot a route to a POI. I have four on my table now doing exactly that. Another symptom may include having to reset the language each time the unit boots or freezing when setting the time. The problem appears to be that either the hard drive is corrupting data written to it, or corrupt files are being written to the hard drive. I have restored one by wiping it, running a low level format with the HD Guru tool (free.) Then when all data is off the drive, run clear flash four times. I can attest to the file corruption because after I run the chkdsk utility on the GPS hdd and it says no problems, after I try to execute a command on one of the flawed units, and check the disk again, it will report fixing more corrupt files. So you then begin to assess a salvage value to the components: used 5" working screen and digitizer $20-$25, housing, fascia, battery and speaker $5 -$10. I tend to keep them around for parts. At first I thought the map file was corrupt, but that proved not to be the case. You can reload Navcores until dawn and it does not help. There is no fix for most units that present with this problem.