Official Answer: Nuvi - SD microSD Card Size - Garmin FAQ

Thanks for the clarification sussamb. I wasn't sure how Express handled that, so it is good to know.

In any case, if you have multiple map files installed on your device, it may be necessary and/or desirable to have a SD card larger than 4 GB.

I may be ordering another micro SD card some for one of my Garmin navigators.

My Garmin Zumo XT will accept a 256 GB card!

https://support.garmin.com/en-US/?faq=UsL6MuMMCM8PpgAhUUCqp7

...but read everything as some special actions may be needed. See below

"microSD/SD memory cards 64 GB or larger cannot be formatted to FAT32 using standard Windows formatting tools. Third-party Windows software may be available which allows the memory card to be formatted in FAT32."

Free disk partitioning software from Paragon or Easeus is arguably the best option for formatting large MicroSD cards in FAT32.

I was thinking about micro SD cards, again, and remembered this post.

It sounds like the simplest thing is to just get 32GB microSD memory cards. That way I can avoid the formatting issue.

Formatting an “oversize” card to FAT32 is certainly not a difficult task. But having said that a 32GB Sandisk card is currently about $12 at Best Buy and around $9 on Amazon. For just the normal use in a GPS, 32GB should be ample for several more years.

An SDHC card and a µSDHC card are different in physical size.
So we are talking about µSDHC cards here.
Any SDHC card is 32GB max.
Fat32 file size is 4GB max.
You can't format anything larger than 32GB to fat32 UNLESS you create multiple partitions.

thank you

I retired a few weeks ago and have been doing some electronics projects around the house. It turns out I had a 32 GB memory card right on my desk under the clutter. So, I deleted some old maps and installed some new ones.

And, yes, I agree that 32GB should be ample for several more years.

Youtube video produced by the former Microsoft engineer who wrote the Windows format routine explaining the Windows format software 32GB size limit:
"Blame Me: The Windows 11 Disk Formatter"
https://www.youtube.com/watch?v=bikbJPI-7Kg&t=45s

The program that I use to format FAT32 single partition μSD cards with sizes greater then 32GB is guiformat.exe. I have formatted many μSD cards with single partitions larger than 32GB without any issues.
"Windows GUI version of fat32format"
http://ridgecrop.co.uk/index.htm?guiformat.htm

A command line version is also available.
"Ridgecrop FAT 32 Formatter"
http://ridgecrop.co.uk/index.htm?fat32format.htm

Mark

My preference is the tool offered by the SD Card Association (Panasonic, Sandisk, Toshiba), SD Memory Card Formatter. It doesn't have a command line version, but does ensure the SD Card is formatted to the specifications given by the companies that set the standard.

https://www.sdcard.org/downloads/formatter/

Since I suggested adding a memory card to your Garmin for additional maps, this might be a good time to remind people a few more details about memory cards.

Note the points below from Garmin.

Important Points About Memory Card Usage:
A device may draw maps more slowly when using a card with a larger capacity if there are too many files and/or large files on the card.

A microSD card with at least 16 GB of space must be used when updating the maps on a device.

See Using a 64 GB microSD/SD Memory Card or Larger for devices below compatible with 64 GB microSD memory cards or larger.

Garmin Express™ will only install a map update to a memory card if there is not enough space on the internal storage of the device.

Maps cannot be moved from the device to a memory card manually.

Exception: Travel Edition devices do not support memory cards, even though they have a memory card slot.

Instructions on where to insert the microSD card can be found in your Device's Owner's Manual.

Some devices have 2 microSD card slots: one for map data and one for dash cam storage.

microSD cards can be purchased from Garmin or other retailers. Garmin offers the 16 GB microSD Class 10 Card with SD Adapter for purchase.

NOTE: Garmin Dash Cams and the dezl DualView require a Class 10 or faster card.

The card may need to be formatted within the device to work.

For instructions, go to the Support Center and enter the product name or the serial number of your device.

Once your device is selected enter “Formatting Camera SD Card" or "Format SD Card” in the search field.

https://support.garmin.com/en-US/?faq=UsL6MuMMCM8PpgAhUUCqp7

The point about manually moving maps is Garnin's "official" line, but not quite accurate as those of us old-timers who used to play around with the cloning method know. Space permitting, you certainly can manually copy and move map .img files and some of the other map-related files (like .jcv, .sid, etc.) back and forth between the internal storage and the SD card on Garmin devices. The trick is knowing the folder and file naming conventions for the specific Garmin model, as Garmin changed these rules over time. So the rules are different for different models (especially on older devices).

Garmin never "officially" acknowledged or supported the cloning method of map installation, so it is not surprising that their support documents do not address copying/moving map files. Their support staff definitely would not want to deal with all the complexities, intricacies and risks of manually copying and moving these files.

While I am in no big hurry, I will start keeping my eyes open for some 32GB microSD memory cards. It seems like Sandisk is the king of such things, but maybe a Samsung or Kingston would work out, too.

Every so often I will see a deal on a 2 pack of these. Maybe when Garmin releases City Navigator North America NT 2027.20 I will upgrade memory when I update maps.

… and I buy them from Best Buy. I have also used Lexar which is currently on sale at Best Buy 32GB for about $17. My neighbor is a regional manager for Best Buy and he tells me the worse place to buy memory cards is an online source like Amazon.

Amazon regards the products as fungible (it's an actual legal term), meaning that a memory card made by brand xyz and labeled as Samsung, is the same regardless of who is selling it. Further, if a warehouse in Brooklyn runs out of stock of the card, the order may be filled from a warehouse in Harrisburg PA, again regardless of who has supplied the cards in any given bin.

So the buyer needs to use caution in purchasing these small commodity items; you may not know what you get, until you get it! And in the instance of memory cards, Best Buy at the Corporate level purchases thousands, perhaps millions of memory cards every year, and they purchase them direct from the authorized importer. They are then disseminated downward to the individual stores as needed. There isn't any unknown middle person, the memory card is supplied from Samsung (Korea) to Best Buy Corporate to the local Best Buy retail store. The odds are much higher in this scenario to get a genuine Samsung memory card.

This was well documented back in 2014 by many sources. Whether it holds true today, and specifically with respect to Samsung memory cards, remains an unknown. But buying the memory card from the retail Best Buy retail store seems to be a better path. “Yes” it might be a buck or two more, but I feel more confident it is genuine.

does the DriveSmart 66 have a memory card slot?

…it does. See https://www8.garmin.com/manuals/webhelp/GUID-6E5DFD2E-EEE4-4...

Note the instructions where it says “Memory cards must use the FAT32 file system format. Memory cards greater than 32 GB must be formatted using the device.” The reason cards larger than 32 GB must be formatted in the device is likely because Windows can’t format a card larger than 32 GB without the user doing something special.

Two of my Facebook Garmin groups had posts on micro SD cards today, too. The Garmin Montana 700i Users Facebook Group had this post:

"After 6 years of owning a Montana 700i I just found out the 32 Bit Microchip SD card has to be a plain card with no hi speed capabilities (like the one used in a camera). I had tried to update my files and started getting strange results."

I checked Garmin.com and it states this:

https://support.garmin.com/en-US/?faq=Le2wG8Ke4p2MK2Ww5IGyK8...

Montana® 700i microSD Card
Memory Card Size Requirements for Garmin Outdoor Handhelds
Many Garmin outdoor handhelds include an expandable memory card slot. For most outdoor handhelds,1 the memory card must meet the below requirements to be compatible:

NOTE: The GPSMAP H1 & H1i Plus devices do not have the same requirements, they support up to a 1TB card with any attributes.

Card type - microSD™ card

Card Speed Class - Class 4 through Class 10

Card storage size - up to 32GB (gigabytes)

SD Card Manufacturer - While any brand of microSD card should work, Garmin has only tested more common brands, such as SanDisk or Kingston

Additional Guidelines for Choosing a MicroSD Card for an Outdoor Handheld
To help determine the card speed class, most microSD cards will be marked with the speed class number inside a circle.

Avoid microSD cards labeled as Plus, Pro, Elite, or Extreme.

Avoid microSD cards rated with a video speed class.

NOTE: These cards will be marked with V6, V10, V30, V60, V90, etc. on the front of the card.

Recommended
The below image is an example of a microSD card with no video speed class rating or Plus, Pro, Elite, or Extreme label. This type of card is recommended for use in our handhelds.

SanDisk 32GB Class 4 Card

Not Recommended
The below image is an example of a microSD card with a video speed class rating. This type of card is not recommended for use in our handhelds.

Ultra Plus Video Class MicroSD Card

1 For a complete list of Garmin outdoor models and their specific memory card requirements, see - Outdoor and Marine Handheld Interface and SD Memory Card Requirements.

Related
Outdoor and Marine Handheld Interface and SD Memory Card Requirements
Formatting a microSD/SD Memory Card for Outdoor Handhelds

The GARMIN GPSMAP 66/67 Owners Facebook Group had this post after someone posted issues with a PNY brand micro SD card:

"The only brand that I find that works without issues in most modern GARMIN devices are Kingston Canvas Select Plus 32GB cards (they are correctly formatted as FAT32), all you need to do is create a GARMIN folder on the card and place the IMG (map) file in that folder on the card."

I am not sure that I agree with everything in the posts above, but Garmin seems to suggest Speed Class 2 to 10 for most Garmin devices. Avoid UHS Speed Class and Video Speed Class for navigation purposes.

Hmmm… as to Official Answer I suspect much of what you published may be applicable to the device referenced, the Montana 700i. I say that because over my 13+ year history of owning Garmin devices, I think I’ve broken virtually all the guidelines you’ve posted without issue.

I will check it out and get a card for the extra space.

I will check it out and get a card for the extra space.