Posting this since all the other posts covering this are now closed.
I had this problem and read all the posts I could find but none of them solved my problems. My problem was solved by powering my Arduino with at least 6V.
All my boards would give me the dreaded "Can't find a FAT16/32 partition" I tried formatting using SDformatter, I quadruple made sure my wiring was correct, I used multiple SD readers and boards. NADA. It was when I happened to change my external power supply to one that put out 6.2V that the card all of the sudden worked!
Previous to this it was powered at 5.2V external supply and everything worked fine (except SD card) I had multiple other cards running, relays, wifi, etc. I never would have expected my problem was power related, especially since the SD card module was found, and the actual card was known to be present, just the formatting part was a problem.
This problem both occurred and was solved on multiple boards and SD card readers including Actual Arduino Megas and Uno's, and also Elegoo Megas, and Uno's.
Hope this helps someone else in the same situation.
