Hi, I´m having the same issue and about to freak out.
iMac retina 2014, just purchased, with Yosemite 10.10.3
I work in photography so I need to download files from SD and CF cards as a regular basis.
With CF card on a Sandisk reader or SD on this same reader that has been working with no trouble until now
http://www.sandisk.es/products/memory-cards/readers/imagemate-all-in-one-usb-30 (no need to use a driver with this device)
I have the same issue as stated above, "disk error -36 cannot read/write" when trying to copy the files to my lacie ssd that is always connected to the computer.
Same trouble happened when connecting the SD in the internal reader of the iMac.
In the internal reader I only get this error
When using the card reader I also receive the error "device has been extracted" (sorry, I dont remember the exact text, but it is the same as when you pull out a pen drive without umounting first)
I try to do all this with my MBP with Mountain Lion and everything works fine.
Any clues on what to do?
Many thanks