USB 3 not working on Yosemite MacOS 10.10.2 I have a MacBookPro11,3, Intel Core i7, 2,5 GHz, ROM: MBP112.0138.B14 with Yosemite natively installed. I also use FileVault.

Here are my problems with external USB 3:


One of my FAT32 external hard drive is not showing up (neither under Finder, nor in Disk Utility).
And for mounted disks (either FAT32, or Mac FS), read/write rate is always thus of USB 1.


The weird thing is that when I use another user account, exchange rate with same hard drives plugged in is thus of USB 3.

Any idea, where the issue could come from? Help very much appreciated, thank you.

So far, I have run Kext Utility and rebooted leaving the external drive plugged in without success.
Have you tried resetting your SMC and NVRAM? Doing both of these can help solve not only this problem but other problems you're having with your system as well. 

See these articles from Apple.com for more details:
Intel-based Macs: Resetting the System Management Controller (SMC)
How to Reset NVRAM on your Mac