I am having a similar issue though I have not seen the read/write error message. Rather, i have had a 256gb micro sd xc card that I had been using in a samsung galaxy A tablet for a year with no issue and I put it in the S9+ phone and in 3 weeks I have had 3 different times where the card (that I have been using to store photos and music and which I have NOT removed) suddenly isnt seen by the phone anymore. Then when I take it out and try removing and re-inserting it the phone says the card is corrupted and needs to be reformatted. I ca't figure out what is corrupting it or how I can prevent it from happening with a new card.
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