Version 6 to Version 7 upgradation issue

HI,

I am using Mikrotik 6.49.7 on architecture x86_64. While trying to upgrade v7 by download “routeros-7.6.1.npk” package, Installation finished after system boot and showing error

ERROR: could not mount the disk
please attached it somewhere else

Please suggest what should I take the action to resolve the issue. Its very urgent

are you upgrading online?