I have an existing Windows 7 in the PC. The hard disk is free from any errors. I decided not to upgrade from Windows 7 to 10 but to get a new hard disk and clean install Window 10. Windows 10 is running fine.

Next I shutdown the PC and plugin Window 7 hard disk into another SATA port. Boot it up and Window 10 comes with message fixing hard disk (chkdsk or something can't remember, it is usually disk corrupt or etc). However the hard disk fixing goes on for a long time. I decide to stop, shutdown, take out Windows 10 hard disk and boot up Windows 7. Under Windows 7 it fix disk, it took not very long it boot to be OK.

I try this a few time, when ever Windows 7 hard disk mount under Windows 10, it will fix hard disk for a long time. It seems Windows 10 does not like Window 7 formatted hard disk.

Any one have any idea how to solve this problem ?
There are a lot of files in the Windows 7 hard disk.
Please help.