Mass copy of 200 usb encrypted drives with same content

I have the following problem to solve: need to copy 6 encrypted movies (50 GB total) onto 200 SanDisk Ultra Fit USB Drives of 64GB capacity. This is a job for a customer.

Then formatted NTFS (to avoid the limit of 4GB per file), I did the encryption process with SanDiskSecureAccess software on one drive. It took 40 minutes and it worked perfectly: entered the password and after a slow decryption process I can open and watch all the movies.

Then I made a disk image with Disk Utility on Mac.
I tried to copy this image to the other flash drives, in order to generate identical clones, but by opening the USB Flash Drive icon in My Vault, it shows me that the content is zero.

How can I solve it without having to encrypt the 200 pendrives, one at a time?
That would be 40 minutes x 200 = 130 hours!!!

What is the best way to do this work, the most rational?

The whole process was performed on an iMac (Retina 5K, 27-inch, 2017, 4.2 GHz Intel Core i7, 48 GB)

Thanks in advance!


If the 6 movies are encrypted you don’t need to use SecureAccess.

The drives come formatted as exFAT which doesn’t have the 4GB limit so no need to reformat them to the hard drive NTFS format.

SecureAccess is drive specific.  Copying doesn’t work.

Thanks, Ed, for your quick response.
Sorry for my erroneous explanation (I’m not english native): movies are not previously encrypted, they are encrypted in Flash Drives with SanDiskSecureAccess, that’s what they were bought for.

The pendrives come formatted in MS-DOS (FAT32), so I have to reformat them. Do you recommend formatting exFAT or NTFS?



All SanDisk drives over 32GB are formatted as exFAT.  If your’s are FAT32 they are not made by SanDisk.

exFAT is designed for large drives, supports files over 4GB.  NTFS is designed for large drives also and supports files over 4GB but is a journeling format designed for hard drives.  Journeling slows down writes to flash drives.

BTW Rather than use SecureAccess to encrypt your files, zip them with a password.  Zip files can easily be copied.

hmmm Do iMacs support exFAT?  That could be a limiting factor.

Hey, Ed,
Encrypting movies (it’s a copyrighted showcase) with SanDiskSecureAccess has the advantage that there’s no copy left on the computer, unless you want to. You can decrypt and watch each movie separately, I think it’s a more professional solution. It works perfectly. In addition, the flash drives have already been purchased.

And to your question: yes, iMacs support exFAT.

I’m already doing it, one flash drive at a time…

Thanks for your help.