I'm having the same issue on my Mac. The properly exported .json file is "an unrecognized format." I've tried on the full and lite clients.

here it describe the steps to migrate BitShares accounts.
http://blog.smartcoin.pw/2015/09/bitshares-how-to-prepare-your-wallet.html

Quote from: lcs on October 16, 2015, 02:06:16 PM
hi, i am trying to imoprt wallet to bts 2.0 but i what i got is, - BitShares Wallet Backup.json is an unrecognized format, when  imoprting keys.
...

As I understand it, a wallet backup should work if you made it from a webwallet.
In a client, you should have used "wallet_export_keys" command.

Quote from: lcs on October 16, 2015, 02:06:16 PM
...
also i got 0.9.3c and my open orders are missing, i can not cancel them or anything , how can i recover funds and transfer them

If I recall correctly, all open orders in BitShares 0.9.3 had to be canceled when migrating to BitShares 2.0.

walletpassphrase "yourpassphrase" 600
dumpprivkey btsAddressHere
wallet_dump_private_key <account name>

hi, i am trying to imoprt wallet to bts 2.0 but i what i got is, - BitShares Wallet Backup.json is an unrecognized format, when  imoprting keys.
also i got 0.9.3c and my open orders are missing, i can not cancel them or anything , how can i recover funds and transfer them to bts 2.0

many thanks