Game crashes when trying to Download Realm

I am trying to download my realm so that I can change the texture pack and reupload it, but every time I try, it appears to complete the download process and moves onto the 'Importing world' screen, then crashes, saying 'The software was closed because an error occurred'. The world is 343.5MB and there are very few other worlds saved on either of our users, so I doubt it is a storage issue