Occasional Reviewer from Michigan "Mark"
It appears that the 32GB SanDisk Ultra Micro SD Card I purchased from Amazon was defective.  I installed it in my Samsung Tablet, but could not successfully transfer files using either a USB cable or WiFi.  The file transfer would appear to start, but then would slow down and hang completely.  It did this on every one of multiple attempts, with different file types, and numbers of files ranging from many to just a single file.  I tried loading files onto the card directly from my PC, but then the Tablet would not see them.  I tried reformatting the card both in my PC and in the Tablet, but still got the same result.  After a few tries, the Tablet would appear to format the card but then tell me that the card was blank/unformatted.  I did an A/B/A with an old 8GB Sandisk Micro SD Card that I had laying around.  It worked perfectly -- formating, transferring files, reading and writing files -- everthing worked.  I put the 32GB SanDisk Ultra Card back in the Tablet, but had the same problems again.  I concluded that the SanDisk Ultra card was defective and returned it.  I'm still using the old 8GB card without a hiccup.The good thing was that Amazon's return policy was quick and painless.