Problems after update to El Capitan

Hello.

Mac OS X Yosemite was a great and stable operation system, but after update to El Capitan on my MacBook Pro major problems detecting every hour and it's unreal to work anymore.

1. When MacBook going to sleep seems that it eject all external drivers. I have external HDD connected via USB and when OS wake up from sleep i always have few message that my device was eject uncorrectly. It's killing my HDD...

2. Sometimes when i wait my MacBook wake up from sleeping it just making auto reboot after unknown crash. I reported 100x times about it via modal window.

3. Finder freezing and Force Quit is not helping. Relaunch Finder is not help too. After few minutes all other apps freezing too.

4. My multifunction printer Samsung SCX-4200 and multifunction photo printer EPSON Stylus Photo PX660 working very well in Yosemite. Both devices printing and scanning documents.

But on El Capitan SCX-4200 detecting only as printer without scan functions. PX660 after install drivers and reboot working well with scan, but after sleep it is not scanning anymore. So i need again delete device, making reboot and scan document if i need.

Please help me to fix each of this issues.

Thanks.