Nuvi255W files corrupt

to get the map files. Your best bet is to call Garmin support (call, don't e-mail). Be nice and see what they will do for your.

OK, I said it in the Subject so I won't say it again.

Before getting into solutions, how do you know the two files are corrupt? Is there any chance that your nuvi has simply unselected City Navigator? (Go to Tools/Settings/Map/MapInfo and see if City Navigator is there and is checked. If there and not checked, just check it.)

The gmapprom files are your City Navigator map files so you've lost your routable map, built in POIs, speed limits, etc. What you're seeing now is your Basemap (assuming that gmapbmap.img is still OK). The gmaptz is the Time Zone map so automatic time zone changes will not occur.

You should have the option in the myGarmin site to reinstall your current map and that would restore a good City Navigator:

https://my.garmin.com/mygarmin/login.htm?service=https%3A%2F...

It's possible that WebUpdater may be able to install a new gmaptz.img file. It's worth a try:

http://www8.garmin.com/products/webupdater/howtoinstall.jsp

If WebUpdater doesn't offer a replacement time zone map, a call to GarminCustomer Service with your device connected to your online computer may let them replace the missing time zone map. Alternately, we've heard that Garmin has no issue with folks sharing files of this sort, so another 255W user may be able to send you the file. Besides being enormous, the City Navigator map files are not something Garmin permits folks to share.

I don't know that a low battery would corrupt these files. Is there a chance you ever had your nuvi connected to a computer and you pulled the USB cable or your computer went to sleep while files were still open or being transferred? It's always safest to use the Safely Remove Hardware function if using a PC.

And, of course, if your nuvi has lifetime maps, there will be a new City Navigator (2014.10) coming out very soon and that'd update your currently corrupt gmapprom map files.

If the two corrupt files have corrupt filenames as well, get back to us. With a corrupt or altered filename, you nuvi likely doesn't have room to reinstall or update City Navigator.

[Update] This Garmin forum discussion suggests that WebUpdater will restore a gmaptz.img file although you may need to remove the old gmaptz.img file first. If so, don't just delete the old file--either rename it to something like gmaptz.img.disabled or move it to a computer hard drive so you'll have it available if you ever need it:

https://forums.garmin.com/archive/index.php/t-31955.html

As usual CraigW has offered some excellent advice.
I would like to make a few suggestions.

As far as downloading the old map that came with your
255W, I don't think you will be able to do it.
I have an old 650 still registered in my name that I gave to my sister. I went to the Garmin site and selected "Manage Maps". There was no option to download the original map, only to buy the current one. It appears Garmin does not keep older maps on their servers to re-download. I don't know how long they keep them, No harm in trying, but don't be surprised if it's not available for you.

If Webupdater doesn't work for you regarding replacing the gmaptz.img file, you can copy it from your Nuvi 40LM that you show it your signature.
The most current gmaptz.img is 584KB according to my Nuvi 2460. Oddly enough my original time zone map I received with the 2460 was 594KB, 10 kb more.

If no "old" map is showing at My Garmin, then you might want to contact them. When I worked on a missing map from a co-workers gps (also not registered), and I registered it, there was no map available for download except the current one. Garmin set it up so I was able to re-download the one that was supposed to be on it. Problem resolved.

How would an .img file get corrupted on a unit?

My understanding is that files get corrupted when they are being saved - so assuming that this .img file once worked, what would corrupt it?

CraigW Nice detailed answer, thank you.
How do I know the files are corrupt? File Explorer says so. Trust me they are. In the past 30 years as a ComSci guy you get to know these things. After running CHKDSK I was able to repair the gmaptz.img file (got back POI’s) etc. However, the gmapprom.img is toast. There are hundreds of link errors etc.
The device was not (recently) connected to the PC. One day it worked, and the next, it did not *sigh*.
By the way I had already done most of the suggestions; Ran WebUpdate, Called Garmin and had a nice long conversation with a very helpful support guy, but he was unable to help as the files for this model are no longer on their server.

You mentioned City navigator?? That is not on this device and do not recall having ever seen it?
Unfortunately the only file that seems to be behaving badly is the gmapprom.img guy.
By the way I did rename the gmaptz.img file and let WebUpdater do its thing – it worked for that file. But, I still get the message ‘no detailed map files . . .’ upon cold boot.
The file names are not corrupt and they can be renamed, but alas not copied.

Odd...gmaptz.img is the timezone map which has nothing at all to do with POIs but if you say that that's what got your POIs back...

Another oddity...ALL nuvis come with City Navigator pre-installed. What on earth was guiding you if it was never installed? The only other routable map on the unit is the basemap (gmapbmap.img) but that is VERY limited in how it will route (only main highways and major roads) and has virtually no detail.

is the map that came on the unit when it was new and is stored in the file gmapprom.img. If Garmin Support will not make the map available to you for download, you would need to purchase the current version of the map, either by download or DVD. On an old unit like the 255 it is probably not worth it.

Another option is to install the free Open Street Map. You will lose some function (TTS and Garmin POI's), but the map can be used for routing and navigation. You can find the Open Street Map precompiled for Garmin devices on this site: http://wiki.openstreetmap.org/wiki/OSM_Map_On_Garmin/Downloa...

Note: the full OSM USA map is very large; about 3.4 GB. So if you want to use the full map on your 255, you will need to put it on a SD card in folder \Garmin and name the file gmapsupp.img.

Following the link to the USA map gives it as 2.6G. Canada is .9G and Mexico is 65MB. Did you mean North America?

I use the USA map compiled by Ben Kenroth. The download is 2.6 GB, delivered as a .ZIP file; 3.4 GB after unzipping.

If those files are corrupt it is because the memory in the Garmin is failing. Those files were written when installed and are not rewritten by the Garmin so could not have happened because of low battery or anything else. The map file is tied to that one unit so no other units map file will work in your unit.

http://www.osmmaps.com/united-states.html

2.6gig. Hope you have a 4 gig memory card.

(gmapprom.img is in Garmin directory

This one is named gmapsupp.img and installed into Garmin Directory on the SD card. No need to rename your old file. Go to tools /settings/ maps and select the new map. Read site Instructions.

Did I blow this one.