Sandisk Nintendo Switch 512 micro sd not holding info

My 512gb micro SD SanDisk Nintendo switch card loads info and then when I unplug it and plug it into my phone, the data is completely gone. What could be the problem?

Hi @JmCkinnon66,

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