I'm having the exact same problem . I Can't Boot Into Installed Deepin OS, the GRUB Screen is Missing After Dual Booting With Windows 10. how can we get the grub?

which disc did you install? if your motherboard have the ufi,and meamwhile you have several discs,set up the disc order in the ufi of the bios.Maybe I can solve your problem but my English is not good enough to explain....Just check if you are using the right disc for starting..for example,,you have disc C  and disc D,and u installed  windows on disc C,deepinlinux in discD,but you  dind not use disc D for starting up。you are using disc C fir start up