after opening wallet getting this error:
"critical error has occured:
Mailformed \uxxxx encoding.
See the console/logfile output for more detailed information!"
can someone tell how to fix it?
Without more information is hard to diagnose your problem. If this is the Windows GUI wallet the best was to inquire and reach a resolution on this would be to open an issue here:
https://github.com/BuckCoin/buck-gui-wallet/issues