Arduino Ethernet Shield R3, SD Card crashes arduino when library included.

[kylemaes]

Any time I use the Ethernet shield and include the SD library my Ethernet doesn't function and the Arduino reboots randomly and does weird things. The SD card can be written to and I have not yet tested reading with the Ethernet on, but the Ethernet once again refuses to function properly (when #include <SD.h> is in the code)...

[lestofante]

Ethernet and sd share the spi connection. You have to use the enable pin to activate only one shield at time. Also pay attention to interrupt, the solution can be a little hard.

[rnearhoof]

I'm not sure if you have this problem solved, but I had the exact same issue on an Uno R3 that ended up being a memory limit.
I was allocating a 1K buffer in the code preamble and the SD card + ethernet libraries use enough memory that it went over the edge. Interestingly, the size of the binary after compiling was only 17,972 bytes (of a 32,256 byte maximum), so I never looked in that direction, but changing my 1K buffer to 512 bytes solved all of the issues.
I found the problem when I ran the same code on an mega2560 and it worked like a charm.

[agdl]

This issue was moved to arduino-libraries/SD#13