Tom Tom one just comes on and then says that there is no GPS devi

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this is the number for tom tom in america

good luck

Go to tom tom website and under tech support, email them your situation, and they should be able to help from there.

Found my manual and got it going. Thank you.

My thanks to the gentleman who posted the link to Tom Tom's solutions link. Although I had been there previously months ago when I first encountered this problem, there had been at that time, no instructions from them on how to properly reset the One that does not have a reset pin hole. That was in March. There are now such instructions.
The key to resetting such a Tom Tom GPS device lies in plugging your One into your computer, which automatically launches Tom Tom Home software (please remember, you have to have Home software installed on your computer already). After doing this:
1. When Home launches, go to Manage My Device Folder (p.2) and click it to open it.
2. You will see a folder-style window which lists all of the items that are your device. Select the folder tab: 'Items on device.' Then Deselect Applications. Click OK when promted. The Applications software will be deleted from your Tom Tom One.
3. IMPORTANT! Then clcik the other folder tab 'Items on computer.' Do the same here by deselcting to uninstal software on your computer as well. Click OK when promted.
4. If you do not get an automatic dialog box indicating that you need new application software installed, return to p.1 and select the folder 'Update My Device.' Follow the instructions as prompted and Tom Tom will both download new computer Home software as well as new software to the One device.
That should do it.
I will tell you that it took me three passes at this process. So it's not a breeze. But in the end it finally worked. And my One, which had been down since March is once again finally up and running with new software and as well as I remember it working.
Hope this helps others.
Tom

Think I have sorted the problem out. I read some of your readers' solutions and it was mentioned that it may be advisable to log onto the GPS update. So, I installed my disc which came with the pack and followed the instructions to download the GPS update (and also took the opportunity to download other updates which took some time). Anyway, used the sat nav this morning and so far, it appears to be working normally now and the signal comes on in seconds!

plug in the usb to pc (computer)
download tom-tom home 2.6
create an account click update my device/one/go
cllick install gps quick fix

i had exactly the same problem, i dont really know how i solved it but first i thought it could be a memory problem slowing the gps signel so i reset the tom tom to factory settings then downloaded the updates from the tom tom home program of corce i lost all my destinations but i didnt want to do a back up just incase one of the updates had a virus or something so if u want to keep them i sugest u write them down first.and then i got a safty pin and pressed the reset button underneath where the memory card goes twice the second time i held it down for about 10 seconds then i looked for updates again from tom tom home. after that in tom tom home there is an option where u can operate your tom tom on your pc so i tryed that and i put in a destination on the pc and clicked on demo tour so i watched the route first it was a bit slow but started to speed up a little. after it had finished i un plugged the sat nav and went for a walk with it around the house soon as i went out side and set a destination it found 6 gps signels,make sure yhe battery is charged to at least half. well i hope anyone who follows my steps gets the same results, thought i lost 200 quid cos i have had it over two years and its only guarenteed for 12 months. well good luck.

need more info of problem

Hello, the same day that I brought my tom tom one I lost the instruction book and the mounting stuff.

Try to reset the device. I used to have a Tom Tom 500, which has the same problem.