Q: sd card doesn't work properly after installing windows 10

     I have a MacBook Pro (Retina, 13-inch, Early 2015) with EL Capitan 10.11.5 and after I installed windows 10 by using bootcamp, everything worked fine at first, but after I deleted my windows portion and then installed windows 10 the second time, the SD seems not functioning properly. It will only mount if the computer is shut down first, then start. If I directly restart the laptop, the SD card will not mount. The same thing happens when I switching between systems by using either option key or bootcamp control centre where when i switched to another system, the SD that was mounted on the previous system will not appear in the new system. I had try to solve this problem by delete the windows portion then reinstall it again, then i found that after I deleted windows portion, the problem is disappeared and it reappeared after I installed windows 10 again. I also found that after i installed windows the total hard drive volume (128g before) became 121g.