Filename copyback problem

I use my SanDisk® Extreme® Portable SSD, 1TB daily to back up most of my data on my D: drive; it never gives me a problem. Today, I copied that data from the SanDisk to a couple USBs so I could reformat the SanDisk, then reformatted it. While copying the files back from the USBs to the SanDisk, I got at least three dozen errors saying the filenames were too long for the target folder - this despite the fact the SanDisk is where these were stored to begin with. Any ideas what might have gone wrong?
Thank you!

Hi @Artseller63
Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for best assistance and troubleshooting: