navigate to the console: Account List -> Advanced Settings -> Console
and type
rescan 340000
You can make a compatible muse chain backup typing this on the console:
type: wallet_export_keys [full path to the file]/[file name].json e.g. on Windows: wallet_export_keys C:\Users\[your user name]\Desktop\keys.json e.g. on Mac: wallet_export_keys /Users/[your user name]/Desktop/keys.json e.g. on Linux: wallet_export_keys /home/[your user name]/Desktop/keys.json
to import to the muse chain the next days it should work like this:
http://docs.bitshares.eu/migration/howto-importing-wallet.html@cob
if we don't import the keys on v0.9.3c and we make it after the snapshot, will we have a problem assuming we can not sync the wallet and scan the latest transactions?