how can i update wallet without losing all my mrai and my 20 mrai address?
just install them. you won't lose your wallet (at least I didn't).
backup your seed just in case.
I cannot open my wallet,, please help
download and install the new wallet (7.4.8 ). I had the same problem with the previous version and 7.4.8 fixed it.
No icnt copy the wallet seed i lost all my mrai
you should've backup the seed right after you received any Mrai. unfortunately I'm not sure what to do in your case.
anywho, this is a trading thread. ask questions on the ANN thread instead.
https://bitcointalk.org/index.php?topic=1381323.0