I am using go-ethereum and web3.
- Is there any way to recover an account if the keystore file is lost?
- Is there any way to recover an account in case of forgotten passphrase?
1) Is there any way to recover account if keystore file is lost?
No. The private key effectively is the account, for all practical purposes.
2) Is there any way to recover account in case of forgot passphrase?
If you remember at least part of your password, then there are tools to attempt recovery, covered in this previous thread:
Unless you reformatted the drive, you almost certainly have it somewhere.
It depends on how strong the password is. If you think the password isn't very strong, there are some fairly elaborate/powerful hashin rigs out there. Your GPU might be able to do it itself, honestly.
Afraid that's all I know. :\