SanDisk MicroSD 128 GB Corrputed

Hello all!,

I have recently run into what I perceive as a catastrophis issue with my memory card. Here’s what happened:

I backed up everything I had on my Note 4 (copied them, thankfully, except a few) and unmounted and removed the card from the phone. I then upgraded it to Android Marshmallow. I inserted teh memory card into my phone and it said that I have to format it to protable storage. No problem with that.

Then I insert it on an adapter into my computer and it tells me that the memory card requires formatting to use it. I tried to remore and re-insert but to no avail. I then tried one of my old phones, a Samsung Galaxy SIII, and it gives me the error " Blank SD card or unsupported file system". 

luckily my laptop still reads it as SD card E:/ hence I turned to TestDisk and another similar utility for recovery, but there it also says the the drive is unreadable.

I checked in the Disk Management section of my laptop and it says that the file type is RAW and there are no partitions or space allocated for it. 

I’m not that grieved about it, other than the fact that it did cost me a lot since I bought it when it came out, but here are my doubts:

  1. Is there anyone else who has faced thiss same issue? if so, please tell me how you approached this problem and the steps you took to manage this

  2. can SanDisk do anything about it?

  3. I have planned on purchasing a SanDisk MicroSD 200GB for my Note 4. I know it’s compatible, but will it cause my device to lag?

  4. Suppose I wish to make this new card part of my internal storage. Can anyone tell me if I can use this same internalized one on anther phone running Marshmallow?

  5.  thsi might be more for Android forums, but can anyone tell me that, if I “format this new memory card as portable storage”, wil it cause this problem in the future? it’s quite heavy on the pocket, this 200GB card!