[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] Sirandar:
Samsung Galaxy S3 Canadian 747 Version and 64GB microSD cards.

New Information: It seems that the S3 on 4.1.1 has issues with both 32 and 64GB cards when you allow "mediaserver" to catalog a complex library. Any card you use for music with the S3 has to be formatted FAT32 and has to have a .nomedia file to prevent Mediaserver form cataloging it. This information comes from 2 independent Galaxy S3s on 2 networks. I currently have a Sandisk 64GB card in my S3 and have been using it for a month without the slightest issue since I formatted FAT32 and prevented cataloging with a .nomedia file.

Summary 1: 64GB cards are currently a bag of hurt ......IMO on Jelly Bean 4.1.1 the Samsung Galaxy S3 does not properly support many 64GB cards. Don't buy them unless you can return and don't waste your time trying to get them to work if they generate any errors(they will only get worse). There seems to be more than 1 problem also .... one is that hard use seems to corrupt some cards and mediaserver also corrupts the card.

Summary 2: Tried Kingston 64GB Class 10 card (SDCX10/64GB) card in may hands it was unstable in this phone either because I got a bad one or due to incompatibility. Wasn't about to try another one.

Summary 3: I tested a 64GB SanDisk microSD card formatted FAT32 and it passed all the stress tests and gave no errors even with the card full of music and repeated switching/manipulations of files on both the phone and the PC. No dismounts,no scandisk errors, no Android mount checking messages.

Hello All ...... Here is how I got a 64GB card to work in the Samsung Galaxy S3 747. It worked for me but may or may not work for you so make sure you can return any card you buy because it is common to have issues.

NOTE1: The S3 does not support exFAT, the format that both Windows 7 and the S3 defaults to when formatting. The exFAT format may appear to work but sooner or later your card won't mount properly on your phone. The card must be formatted FAT32 for Android 4.1.1 (Check other posts on how to do this)

NOTE2: The Samsung default player and the Mediaserver App are buggy pieces of crap for large libraries ... Use PowerAmp media player instead from the play store.

NOTE 3:If you have messed about with exFAT and syncing using a Media Player Program you need to format your card FAT32 on your computer AND remove the offending software and shut down your computer and restart it.

1) First you need to have a look at what you are using to read your microSD card on your PC and if it is more than a year old you should probably throw it out or remember to never put your 64GB card in it. With the right SD card reader you can also take the card out of the phone and transfer directly using the reader but it may not work.

2) If you have programs intercepting your USB mass storage connections on your PC, you need to disable them .... The program I use for music is Media Monkey 4 and if you have the MM4 mass storage sync addins active, not only will you not be able to sync with MM4, you will not be able to transfer files to your phone by any method until all the Mass Storage Hooks are removed. Other program like ITunes may or may not have similar issues. This is important because these programs and hooks can actually render the card inoperable. Media Monkey for example will try to sync the tag track name instead of the actual name to microSD and this can result in improper characters and path lengths in created files that can destroy the card.

3) It is best to just take the card out of the phone and copy all your tracks direct to the card using Windows 7. Make sure you have a current reader that supports 64GB. The sad take home message is that you won't be able to sync using a media file manager but with 64GB of storage you probably don't need to anyway, Just copy your whole library over and forget about it until you get new tracks.

4) Create a directory called Music on your SD card and create or copy a file called .nomedia to that directory. This is required because the Android program Mediaserver will try to catalog this directory if you don't and mediaserver is buggy with music files. This means the Samsung Music Player App won't see your tracks and you will have to use PowerAmp to play tracks (Samsung player is actually pretty good but PowerAmp is better anyway)

5) Copy all your tracks using Windows 7 and a card reader. It is way faster than MTP anyway. Check that the files are there then "Safely remove hardware" the card, remove, and re-insert. If you get errors just take the card back to the store.... don't waste your time (unless you aren't sure about your reader) Run chkdsk (without fix option). If you have errors just take the card back to the store.... don't waste any more time. "Safely remove hardware" and remove the card.

4) Put the card in the phone and carefully watch the status bar. If your card wont mount, or gives you a "checking the card" message the card will never work in your phone so just take it back to the store.. Dismount your card and remove it from the phone.

5) Reinsert the card into your card reader on your PC . If you get errors just take the card back to the store.... don't waste your time Run chkdsk (without fix option). If you have errors just take the card back to the store.... don't waste any more time. "Safely remove hardware" and remove the card and put it back into your phone..

7) If your phone gets laggy when you put the card in it means that you didn't correctly put a .nomedia file into the music directory on your microSD. The buggy mediaserver program is trying to catalog your music and it may corrupt or destroy your card if you have a big collection.

8) Open PowerAMP and do a full rescan. If your card and music are intact a full rescan of 10,000 tracks shouldn't take more than 5 min. If it does your card is struggling or you still have mediaserver trying to catalog the tracks. After catloging is finished test your media library using the PowerAmp specifically looking for albums with unknown artists or album art that doesn't load. If you know that every track has uncorrupted tags and uncorrupted album art on your computer then missing art and unknown artists mean you have a problem with FAT32, the card or your phone. Back to the store with your card, but it is really easy to have corrupt tracks in your library so check that if you like.

9) Note that with a full 64 GB card of music the PowerAmp will take up to 5 minutes to catalog your tracks and your PowerAmp will not work properly during this time AND your battery will be sucked down at an incredible rate due to 100% CPU usage. If you make the mistake of cataloging tracks with PowerAMP with mediaserver active at the same time your phone will grind to a halt and neither PowerAmp or Stock may ever finish cataloging and your battery will be sucked dry for days on end.

10) Remember to never ever stick your microSD card into any reader older than 6 months to a year .... Actually I wouldn't stick it in any reader at all for a year or 2. Writing a single file with a unsupported reader can cause corruption or wipe the entire drive.

11) Enjoy your music collection on your phone and be glad you don't have to use any of the crappy on-line music storage solutions which are SLOW, UN-CATALOGED and WiFi/Carrier DEPENDENT, and which can take weeks to upload your tracks.