Why can't I write/edit files on my SD card, but I can access files already on there just fine?

[AC Question]

I have an unrooted LG G4 with Lollipop 5.1. I've been using an SD card to store music and videos and stuff for several months now, but all of a sudden the other day I couldn't download files to my SD card or delete anything already on there, though I could still access stuff that was already on the card like normal. I tried using ES file explorer, the standard LG file manager, and plugging into my PC. ES file explorer says "task failed" when I try to delete anything or create a folder, LG file manager says failed, and on the PC when I delete a file, it seems like it's deleted, but when I check again later, it's still there.

I haven't updated android versions or really done anything unusual with my phone recently. I still have around 10 GB of space on the card, so it shouldn't be a memory issue. And it doesn't seem like the card is corrupted or anything since I can still access all of the files already on it perfectly. I'm totally confused.

Thanks for your help!

 

[dpham00]

I would try to copy everything to a pc, and reformat the sd card, then copy the stuff back on

 

[Almighty1]

It means the SD Card is failing as the chip on the SD Card will prevent any new writing/delete/edit but will allow you to copy the data that is already there.