I have a problem with nuvi 55 (maps are locked)

Please explain how you tried to install the map to the nuvi.

From Garmin support.

Correcting the message "Can't Unlock Maps" or "Can't Authenticate Maps" on a Garmin device.
If a Garmin device displays the message Can’t Unlock Maps or Can't Authenticate Maps, it has detected a map that cannot be validated for use with that device.

This can be caused by:

Installing a memory card that contains maps intended for a different device.
Copying maps from one device to another.
A problem with the data in the map file.
Incorrect or missing unlock information for an installed map.
To resolve these issues:

If a memory card is inserted into the device, remove the card and restart the device. If the error message no longer displays, there is a locked map on the memory card.
If the memory card was previously used in another device, there are most likely maps installed to the card that are only unlocked to the previous device. The maps will either need to be deleted or reinstalled for the current device to unlock them.
Maps may have been installed to the memory card with MapInstall or MapSource that were not unlocked for the device. Unlock the maps for the device on the computer and then reinstall them to the memory card.
If the memory card was preloaded with the map, contact Product Support.
If the memory card contains maps that were copied from another preloaded card, delete the map files from the card and use the original card. Preloaded maps can not be copied from one card to another.
If these situations do not apply or the issue is not resolved, proceed to the following steps.
If the issue occurred as a result of updating the maps, ensure that Garmin Express is up to date and reinstall the maps. If the device is being updated on a Windows computer, be sure to use the Safely Remove Hardware option after the update has completed. Even though the update appears to complete, the write-caching feature on some computers may have not completely built or transferred the map to the device. Ejecting the device before disconnecting it can prevent this error.1
If this message is displayed after installing a Downloadable Content (DLC) map, reinstall the map and try again. If the issue persists, follow the steps in this FAQ.
If maps have not been installed or updated recently, if an update is available.
Maps may have been installed to the device with MapInstall or MapSource that were not unlocked for the device. Unlock the maps for the device on the computer and then reinstall them to the device.
The Garmin device should now power on without displaying the error message.

1 To safely remove the device:

Press the Windows key + E
Click This PC (Windows 10 only)
Right-click the Garmin device
Click Eject (if there is no Eject option, the device does not need to be ejected).

Other info.

Unlock Maps

If unlocking your maps to this computer for the first time:

Connect your GPS device to your computer's USB port and click the 'Find Devices' button below. When your device is detected, enter the serial number found on your GPS device and the 8-characters product key found on the back of the disc's case (for TOPO maps the product key can be found either on the manual or pasted inside the case on the left side). Then click the 'Unlock Map' button below.

If you have already unlocked your maps and would like to retrieve your existing unlock code(s):

Connect your GPS device to your computer's USB port and click the 'Find Devices' button below. When your device is detected, enter the serial number found on your GPS device and click the 'Retrieve Unlocks' button below.

Zumo Owners:

The maps on your device have already been unlocked before purchasing. Before you begin, please write down the serial number found underneath the battery of your GPS device. Connect your device to your computer's USB port and click the Find Devices button below. When your device is detected, enter the serial number of your GPS device and click the Retrieve Unlocks button below. Once retrieved your MapSource software that has been installed will be ready to use.

hi
thanks for your replay, I install the maps on sd card after I reinstall an older version of nuvi 55 software because the latest update not accept the copied maps.
the it give me is like our friend here (charlesd45) said Can't Unlock Maps).
regards

If the problem continues after trying everything in the FAQ charles provided and if you only tried to update the map once and failed, my suggestion is to delete the files on the SD card, then install the empty SD card into the nuvi 55, then rerun Garmin Express. If Garmin Express states you need a software update and a map update, you could first do the software update only with Garmin Express, disconnect the GPS and power it up to install the software update, then rerun Garmin Express again and do the map update, choosing the Install to SD card option. With luck, this time the map update will install the proper map update and associated files including the map unlocking file.

Prior to downloading the software update, be very sure you have a fully charged battery since the software update will install with the nuvi running only on its battery power and you don't want a software update to fail due to a weak battery causing the nuvi to power down before the update is complete.

Regarding software updates, I assume your failed update tried to update your device to v5.5 which was released June 6 of this year and that you reinstalled an older (5.4, 5.3, 5.2, etc.) version.

http://www8.garmin.com/support/download_details.jsp?id=6779

There are a few quite old threads here regarding reverting to an older software version. The process can be involved and can cause problems so this backdating shouldn't be considered lightly.

The question hasn't come up recently since no one seems to have had a software update issue requiring it. From what I remember, a proper software backdating, even if you still have the older files, can require manually editing a XML file in the nuvi. There was also one software update, that if backdated to an earlier version, would permanently disable a feature of the GPS. It may have been Bluetooth access for the device but I may be wrong.

Since any future map updates will again try to update your software, I think it may be best to first successfully update to the newest software before trying to update to an unlocked new map.

If you have a nüvi 55, what map are you trying to install?

hi
I tried to install (Europe NTU 201620)map.
regards

Stating that you're trying to install version 2016.20 is informative since the current version of the Europe NTU map is 2017.10 released on June 4, 2016.

This site does not discuss updates of Garmin maps except when done through Garmin.

If you purchased the maps, there is a key or authentication code you can type in. If you have lifetime maps, go under your account on garmin.com. Look for the maps, reset the unit and then download.

I had red alert sirens going off in my head last night when I read this thread, but I couldn't confirm my suspicions until lr8rl replied.

@allbizz: He didn't purchase the maps. They were downloaded from a pirate site.

@lr8rl: Buy the maps. If you don't want to buy the maps, there are legitimate third-party sources like Openstreetmap where you can download the maps.