SanDisk 128GB Ultra Dual Drive USB Type-C w/macOS fails to mount

Hi. Just got a 128 GB model of this drive, connecxting w USB-C to a macbook pro running Catalina.
Initially, the new drive was recognizable on being plugged in, formatted FAT32
since i didnt want to run afoul of file size limits, i tried reformatting using Apple Disk Utility, to any of the macos extended journaled variants.
All except FAT32 fail on attempt to remount - although disk util recognizes the drive and displays its capacity (as unmounted) and can reformat.
ERROR: Error 49153
If I format it back to FAT32, it is remountable.
what gives? i’d prefer not to have my file size limited.
what do i need to do to get this to reformat to apple’s file format and allow the machine to mount the disk?


Hi @nerdromancer,

For a hard drive to be able to be read from and written to on both a Windows and macOS computer, it must be formatted to ExFAT or FAT32 file format. FAT32 has several limitations, including a 4 GB per-file limit. This is a file system limitation that affects both macOS’s and Window’s, and the only workaround is to format the drive to exFAT.

thanks. it’s not really windows I am concerned about. I’m on a Mac and when I format it for a Mac, it is unmountable. Any further thoughts? thx

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I had the same issue with my disk not mounting. I left the drive plugged in and when I came back this morning, excessive heat was coming from the drive and the plastic has started melting