Assuming you want to copy everything from the old card to the new one, and you haven't moved apps to the card, connect the phone to a PC or laptop, make a folder on the PC somewhere (C:\, the desktop - anywhere there's enough space), open the phone, open Card, select everything (except moved apps) and drag it to the folder on the PC. Turn the phone off, remove the card, put the new card into the phone, turn the phone on, open the phone (on the PC), open Card and drag everything from the folder you made to the card. (Expect each operation - moving to the folder and moving from the folder - to take a LONG time.)
Do not use a USB hub - connect the phone directly to the laptop or PC. Most hubs can't handle that sort of sustained data streaming.
If you had any apps moved to the card, move them back to the phone before removing the old card. They'll have to be moved to the new card with whatever app you use to move apps to cards. The links on the phone point to specific locations on the old card. Copying the apps to the new card won't put them into the same locations on the new card, so you'll get an "app not installed" error.
If you plan on putting any large files (more than 4GB or videos more than 2GB) on the card, format it as exFAT, not FAT32, before putting any files on it. (Formatting it will erase any files on it.)
Once the copy to the new card is complete, use the "safely remove" icon in the tray (assuming a Windows PC or laptop) before unplugging the phone. The copy may say that it's complete, but Windows, internally, sometimes delays the physical writes to when nothing else is happening, so you'll be removing the phone when parts of the copy haven't actually been written to the phone. "Safely remove" forces Windows to finish all writing to that device before telling you that it's safe to remove it.
01-06-2015 06:13 PM