Is the error for the sd card in the RC2 or the Mini4 ....or both, never received this error till after i did the update the other day.  was reviewing the video i shot yesterday and the first video was real muddy and out of focus then all of a sudden about halfway through it became crystal clear. just messing around so did not matter. would have been a real shame for a once in a lifetime capture of something.

What microSD card are you using?  Brand and speed are important, hopefully you're using the recommended cards.

RobZilla Posted at 2-6 09:52
What microSD card are you using?  Brand and speed are important, hopefully you're using the recommended cards.

its a micro center micro SD HC 32GB  Read speed: up to 80MB/s, Write speed: up to 15MB/s.
i ordered a SanDisk Extreme PRO 64GB V30 U3 A1 microSDHC

Hi there. The error is for the SD in Mini 4 Pro. Additionally, SD card writing speed is related to the current number of files stored on the SD card and how it is used by the user. If the number of files is large, the writing speed will generally be slow. If the user, for example, occasionally deletes the files on the SD card this will lead to more file system fragmentation on the SD card, so that the SD card write speed will slow down. If the SD card writing speed is slow due to too much file fragmentation, try using a computer to format it.

Sandisk Extreme Pro 64 cards will work perfectly, they're more than up to the task. Order one for the controller and one for the mini 4. A note of interest is while I don't really need 256 gig and up cards, I bought 256's as they have a faster write speed than say a 32, 64, or 128 in most all brands, the 256 gig Sandisk Extreme Plus cards I am using now have a write speed of up to 140, plenty fast for 4K video. They are pretty much the same card as the Extreme Pro's. Take all your files off after each flight, and format the cards in the drone and controller with the controller. As DJI Tony mentioned, deleting files on the cards causes fragmentation, and slows down the writing process, which is what is really of concern here.
Here's what I do with my Mini 4 and RC2:
After I'm done flying for the day, I take the card out of the drone and use a card reader to copy the files to a folder on my PC, that way the drones not sitting there cooking away while the files are copied. I always eject the card from the PC, and then put the card back in the drone. Do the same thing to the controller if you like, but as they are smaller files, I usually just plug it into the PC with a USB cable and copy the files off that way, generally just my screen shots and screen recordings anyway. Eject the controller from the PC, and then turn on your drone. Once they're connected, use the controller to format the card in the drone, and then format the card in the controller. I clear all my cache files, and then next time I go flying, I start with a clean slate. It also keeps my files in some kind of sanity on my PC as I just make a new folder for each flying session, and things get organized on the fly with little effort required
There are several ways of getting the files off the drone and controller, try them all and then decide on your own method.

Hello!

I just received an Samsung EVO Plus 128GB V30 U3 A2 microSDXC I. I thought this one would work fine since is one of the cards recommended here https://www.dji.com/mini-4-pro/specs

I know DJI do the list only with the exact sizes tested, the recommendation mention the 512GB but since all the speed classes are the same it shouldn't be really relevant right?

First time that i plugged the card in I got some filesystem error and the card was not getting recognized. After formatting it from the Camera menu it was recognized.

Happily on my way to launch the drone noticed the SD Card Speed Too Slow warning... This one persists even after re-formatting...

I wonder if I bought an counterfeit card or if the card size is influencing it and I should get the 512GB (too much space IMHO) instead the 128GB.

Quick update

After some research I noticed that on some Samsung cards the write speed may vary from one capacity to another even if all the classes are rated the same (V30 U3 A2)

Will try with the SanDisk Extreme PRO 128GB V30 A2 microSDXC

djiuser_xvdiFHltu4jV Posted at 2-22 05:26
Hello!

I just received an Samsung EVO Plus 128GB V30 U3 A2 microSDXC I. I thought this one would work fine since is one of the cards recommended here https://www.dji.com/mini-4-pro/specs

Hi there. You can try formatting the microSD from a computer instead if the issue persists. You can also try using a different SD card to isolate the issue. Have a nice day.

djiuser_xvdiFHltu4jV Posted at 2-22 05:26
Hello!

I just received an Samsung EVO Plus 128GB V30 U3 A2 microSDXC I. I thought this one would work fine since is one of the cards recommended here https://www.dji.com/mini-4-pro/specs

You definitely don't need a 512 card unless you prefer it. In all brands the 256 gig ones will have the same write speed as a 512. Usually the 128 gig write speed will be a bit slower.
Manufacturers also like to keep using the same product name over a span of years for marketing reasons. So my Sandisk extreme plus cards when first introduced were not as fast as the latest ones. You'll see this on ebay and amazon where you see a good deal on a card, it's usually because its the older, slower version of the card being cleared out.
When you look at a manufacturer, or retailers card specs, you want to know write speed and read speed.
If you want to dig deeper, watch some you tube comparison reviews on them. Often you'll see a card will start out writing or reading very quickly and then slow down or the speed will go up and down during a file transfer test.
And as you mentioned one has to be aware of counterfeit cards.