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Garmin Express not recognising SD card

Hi. I've exhausted Garmin on-line support, who seemed not to understand the problem and suggested after a couple of emails that I solve the problem by buying a new Garmin.

I've put as much detail as I can in here, apologies in advance if it's not brief, but hopefully someone can help diagnose the problem.

I have a zumo 660. Appreciate it's an old unit. It's up to date in terms of firmware. I'm running Garmin Express 7.19.0.0 and Windows 11 on a Surface Pro 9. I have a lifetime update licence for the European map set and have successfully taken several upgrades over the years using the licence.

June 2023, I ran into a memory problem and couldn't download the latest European mapset to the zumo. At the suggestion of Garmin Support, I replaced the previous SD card (IIRC it was 8GB but might have been only 4GB) with a larger (32GB) card. The June 23 map update that worked perfectly on the zumo with Garmin Express 7.16.3.0 on my previous Win10 machine.

I've been unable to download the latest map update.

With the zumo connected via USB, GE doesn't recognise the memory card and asks me to select what regional subsets of the Europe map I want to download to the zumo. As far as I can tell, the map upgrade package is just under 9GB, about 600MB larger than the previously installed maps. The SD card only has Garmin map data on it plus some custom routes. No MP3, no user JPG and is showing over 20GB of free capacity with the June 23 maps on it.

I've tried the following, none of which have worked:

  • Reformatted the SD card (several times)
  • Checked the SD card is working. I've done this by restoring the backup of the SD card which contained the June 23 update. Put it back in the Garmin with June 23 map update and everything is OK.
  • Tried to use the old Mapinstall utility to transfer the maps across. Again, this isn't seeing the SD card, thinks the zumo only has its base 4GB memory and asks me to select regions.
  • Tried the method of spoofing GE into thinking the SD card connected directly tothe laptop was in fact the Garmin. I've used this approach, which I found on a GPS forum years ago, several times in the past. It involves some manual intervention but ultimately it's proven faster than using the USB connection. (Further notes on this below)
  • Hard reset the unit (power on + press bottom right of the screen). This hasn't solved the problem.
  • Gone back to my old machine and GE 7.16 but I get the same problem, which makes me think it's something to do with the mapset and any instructions for GE that come with it from Garmin

On the spoofing solution (more on it here - http://www.poi-factory.com/node/39231), please jump to point 9, about having to rename files. What I have found now is in addition to installing the gmapprom.img, gmapprom.gma and gmapprom.unl files, which normally need to be renamed, GE is also installing files gmapsupp.img, gmapsupp.gma and gmapsupp.unl. i.e. installing files that previously the user would have to create by renaming the relevant *prom.* files.

I've tried various permutations of renaming the *prom.* files and the *supp.* files that GE installed, moving the *prom.* files out of the Garmin directory on the card etc., but none of this works. When the SD card is put back in the zumo after using the spoofing method, only the base maps are shown.

Any help welcome.

  • The reason you're seeing gmapprom and gmapsupp files is that the EU map has been split in 2 for many years now as the map is too large to be in one file as it breaks the 4Gb limit of the FAT32 formatting. I assume when you formatted the card you did choose FAT32? If not that would be the issue.

  • Thanks for the response.

    Yes, the card was formatted using FAT32.


    Re: the two gmapprom and gmapsupp files, I can only assume that I used GE with the USB cable the last time I did the update. If I'd been using the "spoofing" method, I'd have noticed the file names already existed and wouldn't have been able to complete the manual rename operation becasue it would have created duplicate file names in the folder.


    What continues to puzzle me is that the previous update from June 23 works fine when reinstalled, yet the same SD card isn't being seen by GE when trying to do the update.

  • Puzzles me too. Only thing further I can suggest is remove the card and run Express. See what happens. You may then be told to insert a sd card, do so at that point. 

  • Thanks again for the assistance.
    Connecting the zumo with the SIM card removed doesn't change the situation and GE doesn't suggest insterting a SIM card.

    It gives me the same prompt at the "Preparing" stage of the process i.e. "Select a Region. The map update is too large to fit on your device. To continue, choose a region to replace Full Coverage of Europe. You can always change regions later if needed"

    I'm then offered regions from the drop down menu. (screen grab attached)

  • OK, so select a region then when it's installed try and change it for a larger one or the whole map. If you can't then install the full map to your PC and use BaseCamp to install the rest of the map to your Zumo

  • Installed one region but when I reconnected the Zumo to try and install other regions, same problem. SD card not being recognised and I'm only allowed to chose one region.

    Tried with Basecamp but again the same problem - SD card not being for transfer - see screen grab below but it is showing under the "Devices List".

  • No screen grab. If it's showing under the devices you should be able to right click it and select Install maps, have you tried that? I assume you have used Express to install the full map to your PC and it's showing in BaseCamp?

  • Sorry about the missing screen shot and thanks again for the continuing support.

    I used GE to install the maps on the PC.

    The pop out with the maps on it appears when I right click and select "Install map"s. The note below the map shows that there is only 4GB free.

    Right clicking and selecting "Device Information" shows that there is 32GB on the SD and plenty of space. The approx 8GB in use currently is the June 2023 map update.

    Just for completeness I've also added a screenshot from File Explorer showing the files on the SD card. Screenshot taken with SD card in zumo and zumo connected via USB.




  • Sorry but those are quite blurred so difficult to read. You should be able to right click the card and select Install maps ... have you tried that?

  • When I try the right click, Basecamp launches Mapinstall, which only shows 4GB free (i.e. back to the root problem of not seeing the SD card) and asks me to select maps up to 4GB in size. This is in spite of Basecamp showing the 32GB card in the Zumo and confirming that when I right click and select "Device Information" rather than "Install Maps".