Apple SDXC Reader stopped working after Catalina upgrade

128 GB cards are problematic on Catalina. You have to 'dummy down' your card ... use one with less memory and slower transfer rate. Catalina is unlikely to function properly with these cards until their next major release with fixes.

San Disk

Extreme PRO, SDHC I on

16 GB 45MB/s is OK

Extreme PRO, SDHC I on

32GB 45MB/s is OK

Extreme PRO, SDXC V30

I on 64 GB 95MB/s is OK

Extreme PRO, SDXC V30

I on 128 GB 95MB/s is OK

However, Apple iMac and other Apple devices cannot support the latest and fastest SD cards being used

by high-end digital photographers. Apple PHOTO application is unable to process

these files and your Apple hardware will produce a number of fault and error

conditions (as well as nothing at all – no action) because the Apple computers

are not keeping up with the demands of the DSLR cameras and big files. I purchased my iMac this month; it has the latest OS. Performance with SD cards is unstable, slow, unpredictable. I've reverted to using my MSFT laptop for photo editing.

Extreme PRO, SDXC V30

I on 128 GB 170MB/s is a FAIL

The only solution is to ‘dummy down’ and use slower SD cards and not Import large numbers of pics

until Apple improves their device and software application capabilities. I suspect

their desire to force everyone onto iCloud is impairing their attention to

photogs who prefer desktop editing and storage.

Emilio,

Gad I’m not the only one going thru this but unfortunately I don’t have the answer either, what I could say is don’t waste time or damage you’re computer by constantly restarting, incoding, or force downgrading to make your EHD compatible again. Looked into all of it wit no luck.

Yes, same for me. The OS upgrades are not sufficiently tested to support these cards. I'm hoping they stabalize their platform in another 6 months. Until then, I edit photos on my MSFT laptop with a 13in display :(

Oh too bad it didn't work for you. I figured maybe it was a fortuitous fluke for me!

San Disk

Extreme PRO, SDHC I on

16 GB 45MB/s is OK

Extreme PRO, SDHC I on

32GB 45MB/s is OK

Extreme PRO, SDXC V30

I on 64 GB 95MB/s is OK

Extreme PRO, SDXC V30

I on 128 GB 95MB/s is OK

However, Apple iMac and other Apple devices cannot support the latest and fastest SD cards being used

by high-end digital photographers. Apple PHOTO application is unable to process

these files and your Apple hardware will produce a number of fault and error

conditions (as well as nothing at all – no action) because the Apple computers

are not keeping up with the demands of the DSLR cameras and big files.

Extreme PRO, SDXC V30

I on 128 GB 170MB/s is a FAIL

The only solution is to ‘dummy down’ and use slower SD cards and not Import large numbers of pics

until Apple improves their device and software application capabilities. I suspect

their desire to force everyone onto iCloud is impairing their attention to

photogs who prefer desktop editing and storage.

I have Catalina and my 3-year old 128 GB SanDisk SD card would not mount. By accident, I got it to work. Here's how.

This SD card is formatted in MS-DOS FAT 32 because it was in a WyzeCam camera to store video data. But the WyzeCam camera would no longer recognize the card, so I wanted to reformat it. When I tried to run Disk Utility First Aid on it, i got the message: Could not mount “disk2s1”. (com.apple.DiskManagement.disenter error 49244.)

1. In the Disk Utility Erase tab, the Erase button for MS-DOS FAT 32 was grayed out.
2. So instead I selected the MacOS file system and then the Erase button was enabled, so I clicked it.
3. This got me a dialog box that the Erase of the MacOS file system had failed (I didn't save the error message).
4. So then I selected MS-DOS FAT 32, and this time the Erase button was enabled!
5. I clicked Erase, and it ran successfully.
6. I went to the Disk Utility First Aid tab, and Disk Utility ran successfully.
7. The SD card now works fine in my WyzeCam again.

A very weird process, and maybe it was just my lucky day, but this worked for me