We have discovered that a corrupted Localization file can cause startup crashes for some users. To see if this will fix any startup problems you may be experiencing please navigate to the game directory location on your device and delete the LocalizationDB.db file.
Here are the paths find and remove the LocalizationDB.db file for each platform:
C:\Users\YOUR USER NAME\AppData\LocalLow\The Pokemon Company International\Pokemon Trading Card Game Online\
Library\Caches\unity.The Pokémon Company International.Pokemon Trading Card Game Online\
This PC\Device Name\Internal storage\Android\data\com.pokemon.pokemontcg\files\
iOS: (Need "iExplorer" program to browse the files on the device, which can only be performed for apps that were installed from HockeyApp.)
Device Name\Apps\Pokemon app\Documents\
You can also fix this issue by uninstalling the game and then reinstalling it. The corrupted localization file is overwritten upon re-installation. Please allow the game to fully update itself before switching to any other programs on your computer or device.
Pokémon TCG Online Senior Community Specialist
The Pokémon Company International
Need help from the support team? Visit the [url="http://www.pokemon.com/support"]support portal[/url] and submit a ticket!