Hi,
Did you install your Mint
AFTER your W10 or
BEFORE?

It makes a difference and there is contention in the boot sector between the 2 OSes. This is true in Ubuntu, Mint, and Puppy Linux. Before your reinstall both your OSes (in case you installed your Mint
BEFORE W10), download the free
EasyBCD; this works good for many of our members, but since I haven't tried it on a UEFI-based BIOS machine, you'll have to try it yourself. I used it a few years ago with good result. (thanks MikeH!).
I can tell you that I personally have run into problems with several of my older non-UEFI BIOS PCs with Ubuntu, my favorite Linux version. One thing you should know is that if you are running a laptop or a netbook with that new version of Mint *is v18 the newest?*, that could be a problem. If you have the latest and you have this dual-boot setup on a laptop or netbook, try reverting to the previous verison of Mint. With Ubuntu I tried for almost 2 years to W10 dual-booting with the newest Ubuntu version, v16.04LTS. That combo NEVER worked!

I had to revert to Ubuntu v14.04.1LTS, the previous version. And that
DID WORK!
Because I have many computers to play with, I was finally able to get v16.04LTS dual-booting with W10 using the W10 built-in BCD menu; on a nearly 10 year old Dell Dimension E520 Desktop PC.
The main thing you should be aware of, especially with netbooks using the old Intel ATOM processor chip; they are underpowered!

At least for the dual-boot W10-Ubuntu combo. I experimentally found that when I was running both wired and Wi-Fi connection to the router for the Internet, my Internet speed dropped from 16 Mbps to 2-4 Mbps!

This was no-Bueno, so I stripped off the Ubuntu from the netbook and the Internet speed immediately went back to 16-18 Mbps!

Since I didn't use the Ubuntu for much on that netbook anyway, I removed it and now only have W10 on it.
If you don't have a netbook or a laptop; then certainly this issue won't apply to you, but it's worth knowing about. OS install order with dual-boot Linux is a big deal and has been going back to Win2k or so. It really became more of an issue with W7/W8x when Microsoft re-wrote their boot-sector code to not play nice with other OSes such as Linux!
Hopefully,
EasyBCD will fix your problem; otherwise you'll likely have to apply one of my other fixes which of course involve reinstalling both OSes in the correct order with W10 being 1st.
Let us know if this helps you.
Too, if you wouldn't mind posting the Make/Model of the computer you are using for this dual-boot combo some of our other folks here might have a further suggestion.
Best,
<<<<<BIGBEARJEDI>>>>>