Updating a lightning node to latest version
Generic update procedure from v0.4.0 to v0.4.1:


stop LND
delete macaroon files in LND directory (to prevent this issue)
install new version exactly like before (as documented above)
start LND 
unlock wallet with lncli unlock to create new macaroon files


In case you are following my RaspiBolt guide, you might want to copy the macaroon file to the admin home directory again: sudo cp /home/bitcoin/.lnd/admin.macaroon /home/admin/.lnd/ (see more details here)