Q: 13" macbookpro mid 2010,

Only RAM which specifically states it is for mid-2010 MacBook Pro will work.  These are the best rated vendors/

http://www.macsales.com/ (OWC) http://www.crucial.com/ http://www.datamem.com/ http://www.lifetimememory.com/

No ValueRAM, no RAM that only says "1067 2 GB memory module, SODIMM DDR3, 204 pin" on it will necessarily work.

You must indicate the age and the model to the store, and get life time warranty RAM.

From a database called Mactracker 7.4.5. Good sources for RAM are OWC, DataMem, and Crucial. However, RAM need not state it is specifically for your model. Any RAM that meets the specifications for your model should be used.

Because you did not specify the specs I posted are for the 13" model. The 15" and 17" models have a maximum allowed of 8 GBs.