1. tonyvr4's Avatar
    I have been having problems with MicroSD cards since I got my LG G3 AT&T D850.
    I have tried two different cards and made sure the card is genuine

    The cards will work for a little while the the phone either does not recognize it anymore or it shows "SD card dismounted"
    Either way, at that point the phone stops recognizing the card

    The cards that I have tried are a SanDisk 128GB Ultra. I also have a 64GB card that I have not tried yet

    I have tried formatting the card in the phone and then leaving it in. Then copying files by USB from my pc.
    It seems like hit or miss is a file copies. I tried copying some photos and some copied fine and others were corrupted and do not display

    I also tried formatting the card on my pc, then coping my files to the card before inserting it into the phone. This did not seem to make a difference

    Any suggestions will be greatly appreciated
    01-20-2015 11:26 PM
  2. Rayfire's Avatar
    Based on what you said, it's still a hit or miss when copying while it's plugged in via USB, I think the problem is the MicroSD. To check this, get your MicroSD and plug it to the adapter that came with it, then plug that to your PC's SD slot (hopefully you have one), see if it will read/copy files. If that works then it might be the MicroSD slot/mount on your phone is broken. Try to borrow someone else's device that can use MicroSD and see if your MicroSD would work on their phone. Basically just hardware troubleshooting is my advice.

    I have a Samsung 64GB and it works fine, even the 32GB that I initially purchased (which was a mistake, needed more) was working fine too.

    EDIT: I just noticed you did say formatting the card on your pc, then copied, but still no go on the phone. I suggest contacting your seller/retailer about your MicroSD warranty check.
    01-21-2015 01:05 AM
  3. Rukbat's Avatar
    1) If you're copying files larger than 4GB, the card has to be formatted as exFAT. A FAT32 card is limited to 4GB file size.

    2) Go to SanDisk microSD Tech Support and open a live chat for assistance. A SanDisk card shouldn't do that.
    01-21-2015 01:07 AM
  4. tonyvr4's Avatar
    I totally agree. When I took the card out of the package I just inserted it into the adapter, then into my pc, and copied the files.
    It wasn't until after having a problem that I did a quick format of the card in the adapter on my pc.

    I am formatting the card in my pc now but not a quick format. We will see

    I was copying some huge files, some large files. I looked and some were a little over 1G but nothing larger than that

    It is possible I was doing something wrong. What is the correct procedure for safely disconnecting the G3 phone from the pc USB connection?
    01-21-2015 09:43 AM
  5. tardus's Avatar
    ...What is the correct procedure for safely disconnecting the G3 phone from the pc USB connection?
    Just make certain the the copying is completed before disconnecting the USB. If you're using Windows don't pay attention to safe disconnect. That is just Windows nonsense.
    01-21-2015 10:38 AM
  6. tonyvr4's Avatar
    I tried some more tests today and it appears that if I copy (or download) any large file to the card while it is in the phone, such as a 1G video, the card crashes and dismounts.
    I can Copy large files to it on my PC but not on the phone

    Oh, I forgot to mention. When this happens I put the card in my computer and it says the card is not formatted
    01-21-2015 12:07 PM
  7. tonyvr4's Avatar
    I contacted LG today and they suggested doing a factory reset. What is the best way to backup contacts, settings and everything so I can put it back?

    Also, every SanDisk card I tried did not work in the G3. Their support was rather sarcastic and useless when I contacted them.
    Last time I every buy one of their products
    01-21-2015 06:15 PM
  8. tonyvr4's Avatar
    After a long time of trial and purchasing many cards, that were supposed to be genuine, I have found the problem.

    The SD card corruption and other issues are all related to fake SD cards. I bought a Samsung 128GB card from amazon and it works perfectly!

    The key to finding the fake cards seems to be the numbers on the back of the card.
    02-10-2015 11:33 AM

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