Formatting a new 2TB External Drive

[rakemup]

I may have messed up. I dual boot Mint11 and Mint12 (that's all for now). I installed my new external HDD and copied lots of files to it. Now I realise that I probably should have re-formatted it to EXT4 before using it. It's now formatted NTFS.

Will I run into issues with it formatted this way?
Can I reformat it to EXT4 and not lose the data I've already moved to it?
---- or should I leave it the way it is?

THANKS

[mank_in]

You can not.
The best solution is backup your data in another hard drive and restore back your data after conversion.
The issue with NTFS is fragmented files