problem with Windows 11 and 10 …i decided to back up a large ( 300gb ) folder from my win11 laptop and move it to an external hard drive that i normally have attached to my main PC that runs win10 , i took about an hour to move it across , i then played a video or 2 in the folder now on the external drive to check all was ok…it was. i shut down laptop and detached external drive then go plug this into my win10 pc…you know where this story is going ! thats right the folder doesnt show up now on the external hard drive ( this has happened before) so why ? and how can i see this folder ?? this is a very bad problem, Microsoft need to stop this from happening, before you ask the hard drive is only a month or 2 old bought brand new , i have run chkdsk all is ok, i unhid hidden folders from control panel that didnt help, please help me

as i say this exact issue has happened before with a different external drive and different laptop it seems to be a microsoft issue ( i assume) in not recognising a folder made while external hard drive was on a different pc