Please clarify. Do you mean that you have both Windows 7 and 10 multibooting on the same machine? If so, is Windows 7 installed and booting in UEFI or Legacy (MBR) mode? Each OS should be booting in UEFI mode for best results.
Additionally, ensure that Fast Startup in Windows 10 is disabled, as it can cause all kinds of bad karma for Linux. You might find some useful information in Multiboot Windows and Linux on Separate Disks.
That is all.